[alsa-devel] Fwd: ALSA queries
---------- Forwarded message --------- From: Chakravarthi Pradeep doubleq7@gmail.com Date: Sun 5 Aug, 2018, 14:19 Subject: Re: [alsa-devel] ALSA queries To: tiwai@suse.de
Hello Takashi,
Thanks for your reply.
periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
periods_min = the minimal number of periods : what is meaning of periods , is it minimal number of interrupts ? period_bytes_min = the minimal size of bytes for one period : it means, minimal size of bytes per interrupt in case of device, Is it correct ? what about period_max ?
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
I'm attaching my driver thread along with this mail. Can you please let me know if I have missed something in audio thread. ?. How to make sure in driver that, trigger stop should be called only when stop command is sent from application.
I'm getting cut cut cut ... noise along with audio in VLC application. Initially for 2 or 4 seconds, cut cut cut noise is not heard in VLC application, However after almost after 5 sec ,I can hear cut cut cut noise in VLC application. With my analysis, hwptr is getting updated properly however I have doubt in app_ptr. I'm attaching the excl sheet with hw_ptr,app_ptr and buf_pos values.
How to remove the cut cut cut ... noise in audio ?
Regards, Chakravarthi
On Fri, Aug 3, 2018 at 1:05 PM Takashi Iwai tiwai@suse.de wrote:
On Thu, 02 Aug 2018 16:31:13 +0200, Chakravarthi Pradeep wrote:
I'm working on ALSA driver for PCIe card. My ALSA driver and it's initializing struct snd_pcm_hardware with below parameter.
/************************ code start ************************************************/ static struct snd_pcm_hardware audio_pcm_hardware = { .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_RESUME ), .formats = (SNDRV_PCM_FORMAT_S16_LE | SNDRV_PCM_FORMAT_S24_LE), .rates = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 | SNDRV_PCM_RATE_96000 | SNDRV_PCM_RATE_192000), .rate_min = 44100, .rate_max = 192000, .channels_min = 2, .channels_max = 8, .buffer_bytes_max = 76800, /*75 kbytes */ .period_bytes_min = 512,//4410, /* (channel (2) * sample_rate (44100)
- bit width (24)) / (60 * 8) */
.period_bytes_max = 16*1024, .periods_min = 10, .periods_max = 255,
}; /************************ code end ************************************************/
- I did not understand what is significance of periods_min ,
period_bytes_min , period_bytes_max and periods_max. Can you please tell me what is importance of these parameter and what value should be mentioned according into ALSA.
These three defines the values your hardware may accept: periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
- snd_pcm_ops trigger callback is getting called in the driver when
application sends "start" command. But ALSA driver is stopping by itself after one frame is copied to ALSA framework, without waiting for "stop" command.
For instance: In trigger callback , I'm getting these logs after one frame is copied. Trigger:Start (When Play button is selected/clicked in application, Start command is sent to ALSA driver) Dma transfer is completed. Trigger:Stop. (When Stop button is selected/clicked in application, Stop command is sent to ALSA driver. But stop button is not clicked in this case)
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
Takashi
On Sun, 05 Aug 2018 20:09:47 +0200, Chakravarthi Pradeep wrote:
---------- Forwarded message --------- From: Chakravarthi Pradeep doubleq7@gmail.com Date: Sun 5 Aug, 2018, 14:19 Subject: Re: [alsa-devel] ALSA queries To: tiwai@suse.de
Hello Takashi,
Thanks for your reply.
periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
periods_min = the minimal number of periods : what is meaning of periods , is it minimal number of interrupts ?
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
period_bytes_min = the minimal size of bytes for one period : it means, minimal size of bytes per interrupt in case of device, Is it correct ?
Correct.
what about period_max ?
The maximal number of periods, the counter-part of periods_min.
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
I'm attaching my driver thread along with this mail. Can you please let me know if I have missed something in audio thread. ?. How to make sure in driver that, trigger stop should be called only when stop command is sent from application.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause.
I'm getting cut cut cut ... noise along with audio in VLC application. Initially for 2 or 4 seconds, cut cut cut noise is not heard in VLC application, However after almost after 5 sec ,I can hear cut cut cut noise in VLC application. With my analysis, hwptr is getting updated properly however I have doubt in app_ptr. I'm attaching the excl sheet with hw_ptr,app_ptr and buf_pos values.
Do the buffer size and period size are set really as expected? Often the driver misses the fact that PCM core doesn't guarantee the alignment of buffer size and period size unless specified explicitly via hw constraints. That is, as default, it's possible to set a buffer size 3000 bytes for the period size 64 bytes. Then the last period is partial.
For aligning the period and the buffer sizes, call snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); in the open callback.
Takashi
How to remove the cut cut cut ... noise in audio ?
Regards, Chakravarthi
On Fri, Aug 3, 2018 at 1:05 PM Takashi Iwai tiwai@suse.de wrote:
On Thu, 02 Aug 2018 16:31:13 +0200, Chakravarthi Pradeep wrote:
I'm working on ALSA driver for PCIe card. My ALSA driver and it's initializing struct snd_pcm_hardware with below parameter.
/************************ code start ************************************************/ static struct snd_pcm_hardware audio_pcm_hardware = { .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_RESUME ), .formats = (SNDRV_PCM_FORMAT_S16_LE | SNDRV_PCM_FORMAT_S24_LE), .rates = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 | SNDRV_PCM_RATE_96000 | SNDRV_PCM_RATE_192000), .rate_min = 44100, .rate_max = 192000, .channels_min = 2, .channels_max = 8, .buffer_bytes_max = 76800, /*75 kbytes */ .period_bytes_min = 512,//4410, /* (channel (2) * sample_rate (44100)
- bit width (24)) / (60 * 8) */
.period_bytes_max = 16*1024, .periods_min = 10, .periods_max = 255,
}; /************************ code end ************************************************/
- I did not understand what is significance of periods_min ,
period_bytes_min , period_bytes_max and periods_max. Can you please tell me what is importance of these parameter and what value should be mentioned according into ALSA.
These three defines the values your hardware may accept: periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
- snd_pcm_ops trigger callback is getting called in the driver when
application sends "start" command. But ALSA driver is stopping by itself after one frame is copied to ALSA framework, without waiting for "stop" command.
For instance: In trigger callback , I'm getting these logs after one frame is copied. Trigger:Start (When Play button is selected/clicked in application, Start command is sent to ALSA driver) Dma transfer is completed. Trigger:Stop. (When Stop button is selected/clicked in application, Stop command is sent to ALSA driver. But stop button is not clicked in this case)
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900 [1.2 <text/html; UTF-8 (quoted-printable)>]
static int uhdc_audio_thread(void *data) { char *audio_frame = NULL; int count = 0; uhdc_t3_card_driver *drv = (uhdc_t3_card_driver *)data; struct snd_pcm_runtime *runtime = drv->substream->runtime;
audio_frame = kmalloc(MAX_AUDIO_SIZE, GFP_DMA); if(!audio_frame) { return -ENOMEM; } while(1) {
if (kthread_should_stop()) { dbg_alsa( "###### %s %d\n",__FUNCTION__,__LINE__); break; } dbg_alsa( "###### Waiting for audio signal %s_%d\n",__FUNCTION__,__LINE__); wait_event_interruptible (audio_interrupt, (atomic_read (&audio_data_ready))); atomic_set (&audio_data_ready, 0); g_count = get_audio_size(g_temp_lro); count = g_count; printk( "######audio signal received and audio size:%d runtime->period_size:%d %s_%d\n",g_count,runtime->period_size,__func__,__LINE__);/* dma read is done here */ /* audio_frame contains audio data */ memcpy(drv->substream->runtime->dma_area + drv->buf_pos ,audio_frame,count);
/* update the buf_pos */ // here the (auto)increase of buf_pos is handled drv->buf_pos += count; drv->buf_pos %= drv->pcm_buffer_size;printk("\n\n\n hwptr=%d appl=%d pos=%d\n", (int)frames_to_bytes(runtime,runtime->status->hw_ptr),(int)frames_to_bytes(runtime, runtime->control->appl_ptr),drv->buf_pos); /* Below line needs to be uncommented for pointer to be updated in the alsa lib */ snd_pcm_period_elapsed(drv->substream); try_to_freeze();
}
kfree(audio_frame); audio_frame = NULL;
return 0 ;
} [3 hwptr_app_ptr_buf_pos_analysis.xlsx <application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (base64)>]
Hello Takashi,
Thanks for your explanation about period and periods.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause
I'm calling snd_pcm_period_elapsed() in my audio thread snd_pcm_period_elapsed(drv->substream); I'm calling this <snd_pcm_period_elapsed()> function after one frame is copied to from PCIe device. However, hwptr is not updated and no sound in the VLC application.
Regards, Chakravarthi Pradeep K On Mon, Aug 6, 2018 at 2:09 PM Takashi Iwai tiwai@suse.de wrote:
On Sun, 05 Aug 2018 20:09:47 +0200, Chakravarthi Pradeep wrote:
---------- Forwarded message --------- From: Chakravarthi Pradeep doubleq7@gmail.com Date: Sun 5 Aug, 2018, 14:19 Subject: Re: [alsa-devel] ALSA queries To: tiwai@suse.de
Hello Takashi,
Thanks for your reply.
periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
periods_min = the minimal number of periods : what is meaning of periods , is it minimal number of interrupts ?
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
period_bytes_min = the minimal size of bytes for one period : it means, minimal size of bytes per interrupt in case of device, Is it correct ?
Correct.
what about period_max ?
The maximal number of periods, the counter-part of periods_min.
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
I'm attaching my driver thread along with this mail. Can you please let me know if I have missed something in audio thread. ?. How to make sure in driver that, trigger stop should be called only when stop command is sent from application.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause.
I'm getting cut cut cut ... noise along with audio in VLC application. Initially for 2 or 4 seconds, cut cut cut noise is not heard in VLC application, However after almost after 5 sec ,I can hear cut cut cut noise in VLC application. With my analysis, hwptr is getting updated properly however I have doubt in app_ptr. I'm attaching the excl sheet with hw_ptr,app_ptr and buf_pos values.
Do the buffer size and period size are set really as expected? Often the driver misses the fact that PCM core doesn't guarantee the alignment of buffer size and period size unless specified explicitly via hw constraints. That is, as default, it's possible to set a buffer size 3000 bytes for the period size 64 bytes. Then the last period is partial.
For aligning the period and the buffer sizes, call snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); in the open callback.
Takashi
How to remove the cut cut cut ... noise in audio ?
Regards, Chakravarthi
On Fri, Aug 3, 2018 at 1:05 PM Takashi Iwai tiwai@suse.de wrote:
On Thu, 02 Aug 2018 16:31:13 +0200, Chakravarthi Pradeep wrote:
I'm working on ALSA driver for PCIe card. My ALSA driver and it's initializing struct snd_pcm_hardware with below parameter.
/************************ code start ************************************************/ static struct snd_pcm_hardware audio_pcm_hardware = { .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_RESUME ), .formats = (SNDRV_PCM_FORMAT_S16_LE | SNDRV_PCM_FORMAT_S24_LE), .rates = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 | SNDRV_PCM_RATE_96000 | SNDRV_PCM_RATE_192000), .rate_min = 44100, .rate_max = 192000, .channels_min = 2, .channels_max = 8, .buffer_bytes_max = 76800, /*75 kbytes */ .period_bytes_min = 512,//4410, /* (channel (2) * sample_rate (44100)
- bit width (24)) / (60 * 8) */
.period_bytes_max = 16*1024, .periods_min = 10, .periods_max = 255,
}; /************************ code end ************************************************/
- I did not understand what is significance of periods_min ,
period_bytes_min , period_bytes_max and periods_max. Can you please tell me what is importance of these parameter and what value should be mentioned according into ALSA.
These three defines the values your hardware may accept: periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
- snd_pcm_ops trigger callback is getting called in the driver when
application sends "start" command. But ALSA driver is stopping by itself after one frame is copied to ALSA framework, without waiting for "stop" command.
For instance: In trigger callback , I'm getting these logs after one frame is copied. Trigger:Start (When Play button is selected/clicked in application, Start command is sent to ALSA driver) Dma transfer is completed. Trigger:Stop. (When Stop button is selected/clicked in application, Stop command is sent to ALSA driver. But stop button is not clicked in this case)
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900 [1.2 <text/html; UTF-8 (quoted-printable)>]
static int uhdc_audio_thread(void *data) { char *audio_frame = NULL; int count = 0; uhdc_t3_card_driver *drv = (uhdc_t3_card_driver *)data; struct snd_pcm_runtime *runtime = drv->substream->runtime;
audio_frame = kmalloc(MAX_AUDIO_SIZE, GFP_DMA); if(!audio_frame) { return -ENOMEM; } while(1) { if (kthread_should_stop()) { dbg_alsa( "###### %s %d\n",__FUNCTION__,__LINE__); break; } dbg_alsa( "###### Waiting for audio signal %s_%d\n",__FUNCTION__,__LINE__); wait_event_interruptible (audio_interrupt, (atomic_read (&audio_data_ready))); atomic_set (&audio_data_ready, 0); g_count = get_audio_size(g_temp_lro); count = g_count; printk( "######audio signal received and audio size:%d runtime->period_size:%d %s_%d\n",g_count,runtime->period_size,__func__,__LINE__); /* dma read is done here */ /* audio_frame contains audio data */ memcpy(drv->substream->runtime->dma_area + drv->buf_pos ,audio_frame,count); /* update the buf_pos */ // here the (auto)increase of buf_pos is handled drv->buf_pos += count; drv->buf_pos %= drv->pcm_buffer_size; printk("\n\n\n hwptr=%d appl=%d pos=%d\n", (int)frames_to_bytes(runtime,runtime->status->hw_ptr),(int)frames_to_bytes(runtime, runtime->control->appl_ptr),drv->buf_pos); /* Below line needs to be uncommented for pointer to be updated in the alsa lib */ snd_pcm_period_elapsed(drv->substream); try_to_freeze(); } kfree(audio_frame); audio_frame = NULL; return 0 ;} [3 hwptr_app_ptr_buf_pos_analysis.xlsx <application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (base64)>]
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
On Mon, 06 Aug 2018 14:29:26 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
Thanks for your explanation about period and periods.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause
I'm calling snd_pcm_period_elapsed() in my audio thread snd_pcm_period_elapsed(drv->substream); I'm calling this <snd_pcm_period_elapsed()> function after one frame is copied to from PCIe device. However, hwptr is not updated and no sound in the VLC application.
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
Takashi
Regards, Chakravarthi Pradeep K On Mon, Aug 6, 2018 at 2:09 PM Takashi Iwai tiwai@suse.de wrote:
On Sun, 05 Aug 2018 20:09:47 +0200, Chakravarthi Pradeep wrote:
---------- Forwarded message --------- From: Chakravarthi Pradeep doubleq7@gmail.com Date: Sun 5 Aug, 2018, 14:19 Subject: Re: [alsa-devel] ALSA queries To: tiwai@suse.de
Hello Takashi,
Thanks for your reply.
periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
periods_min = the minimal number of periods : what is meaning of periods , is it minimal number of interrupts ?
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
period_bytes_min = the minimal size of bytes for one period : it means, minimal size of bytes per interrupt in case of device, Is it correct ?
Correct.
what about period_max ?
The maximal number of periods, the counter-part of periods_min.
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
I'm attaching my driver thread along with this mail. Can you please let me know if I have missed something in audio thread. ?. How to make sure in driver that, trigger stop should be called only when stop command is sent from application.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause.
I'm getting cut cut cut ... noise along with audio in VLC application. Initially for 2 or 4 seconds, cut cut cut noise is not heard in VLC application, However after almost after 5 sec ,I can hear cut cut cut noise in VLC application. With my analysis, hwptr is getting updated properly however I have doubt in app_ptr. I'm attaching the excl sheet with hw_ptr,app_ptr and buf_pos values.
Do the buffer size and period size are set really as expected? Often the driver misses the fact that PCM core doesn't guarantee the alignment of buffer size and period size unless specified explicitly via hw constraints. That is, as default, it's possible to set a buffer size 3000 bytes for the period size 64 bytes. Then the last period is partial.
For aligning the period and the buffer sizes, call snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); in the open callback.
Takashi
How to remove the cut cut cut ... noise in audio ?
Regards, Chakravarthi
On Fri, Aug 3, 2018 at 1:05 PM Takashi Iwai tiwai@suse.de wrote:
On Thu, 02 Aug 2018 16:31:13 +0200, Chakravarthi Pradeep wrote:
I'm working on ALSA driver for PCIe card. My ALSA driver and it's initializing struct snd_pcm_hardware with below parameter.
/************************ code start ************************************************/ static struct snd_pcm_hardware audio_pcm_hardware = { .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_RESUME ), .formats = (SNDRV_PCM_FORMAT_S16_LE | SNDRV_PCM_FORMAT_S24_LE), .rates = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 | SNDRV_PCM_RATE_96000 | SNDRV_PCM_RATE_192000), .rate_min = 44100, .rate_max = 192000, .channels_min = 2, .channels_max = 8, .buffer_bytes_max = 76800, /*75 kbytes */ .period_bytes_min = 512,//4410, /* (channel (2) * sample_rate (44100)
- bit width (24)) / (60 * 8) */
.period_bytes_max = 16*1024, .periods_min = 10, .periods_max = 255,
}; /************************ code end ************************************************/
- I did not understand what is significance of periods_min ,
period_bytes_min , period_bytes_max and periods_max. Can you please tell me what is importance of these parameter and what value should be mentioned according into ALSA.
These three defines the values your hardware may accept: periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
- snd_pcm_ops trigger callback is getting called in the driver when
application sends "start" command. But ALSA driver is stopping by itself after one frame is copied to ALSA framework, without waiting for "stop" command.
For instance: In trigger callback , I'm getting these logs after one frame is copied. Trigger:Start (When Play button is selected/clicked in application, Start command is sent to ALSA driver) Dma transfer is completed. Trigger:Stop. (When Stop button is selected/clicked in application, Stop command is sent to ALSA driver. But stop button is not clicked in this case)
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900 [1.2 <text/html; UTF-8 (quoted-printable)>]
static int uhdc_audio_thread(void *data) { char *audio_frame = NULL; int count = 0; uhdc_t3_card_driver *drv = (uhdc_t3_card_driver *)data; struct snd_pcm_runtime *runtime = drv->substream->runtime;
audio_frame = kmalloc(MAX_AUDIO_SIZE, GFP_DMA); if(!audio_frame) { return -ENOMEM; } while(1) { if (kthread_should_stop()) { dbg_alsa( "###### %s %d\n",__FUNCTION__,__LINE__); break; } dbg_alsa( "###### Waiting for audio signal %s_%d\n",__FUNCTION__,__LINE__); wait_event_interruptible (audio_interrupt, (atomic_read (&audio_data_ready))); atomic_set (&audio_data_ready, 0); g_count = get_audio_size(g_temp_lro); count = g_count; printk( "######audio signal received and audio size:%d runtime->period_size:%d %s_%d\n",g_count,runtime->period_size,__func__,__LINE__); /* dma read is done here */ /* audio_frame contains audio data */ memcpy(drv->substream->runtime->dma_area + drv->buf_pos ,audio_frame,count); /* update the buf_pos */ // here the (auto)increase of buf_pos is handled drv->buf_pos += count; drv->buf_pos %= drv->pcm_buffer_size; printk("\n\n\n hwptr=%d appl=%d pos=%d\n", (int)frames_to_bytes(runtime,runtime->status->hw_ptr),(int)frames_to_bytes(runtime, runtime->control->appl_ptr),drv->buf_pos); /* Below line needs to be uncommented for pointer to be updated in the alsa lib */ snd_pcm_period_elapsed(drv->substream); try_to_freeze(); } kfree(audio_frame); audio_frame = NULL; return 0 ;} [3 hwptr_app_ptr_buf_pos_analysis.xlsx <application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (base64)>]
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
Hello Takashi,
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
I'm sure that I'm calling snd_pcm_period_elapsed() function and my pointer function is given below:
/************************* pointer callback ***************** static snd_pcm_uframes_t uhdc_audio_pcm_pointer(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; uhdc_t3_card_driver *drv = runtime->private_data; return bytes_to_frames(runtime, drv->buf_pos); }
Regards, Chakravarthi Pradeep K
On Mon, Aug 6, 2018 at 6:21 PM Takashi Iwai tiwai@suse.de wrote:
On Mon, 06 Aug 2018 14:29:26 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
Thanks for your explanation about period and periods.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause
I'm calling snd_pcm_period_elapsed() in my audio thread snd_pcm_period_elapsed(drv->substream); I'm calling this <snd_pcm_period_elapsed()> function after one frame is copied to from PCIe device. However, hwptr is not updated and no sound in the VLC application.
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
Takashi
Regards, Chakravarthi Pradeep K On Mon, Aug 6, 2018 at 2:09 PM Takashi Iwai tiwai@suse.de wrote:
On Sun, 05 Aug 2018 20:09:47 +0200, Chakravarthi Pradeep wrote:
---------- Forwarded message --------- From: Chakravarthi Pradeep doubleq7@gmail.com Date: Sun 5 Aug, 2018, 14:19 Subject: Re: [alsa-devel] ALSA queries To: tiwai@suse.de
Hello Takashi,
Thanks for your reply.
periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
periods_min = the minimal number of periods : what is meaning of periods , is it minimal number of interrupts ?
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
period_bytes_min = the minimal size of bytes for one period : it means, minimal size of bytes per interrupt in case of device, Is it correct ?
Correct.
what about period_max ?
The maximal number of periods, the counter-part of periods_min.
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
I'm attaching my driver thread along with this mail. Can you please let me know if I have missed something in audio thread. ?. How to make sure in driver that, trigger stop should be called only when stop command is sent from application.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause.
I'm getting cut cut cut ... noise along with audio in VLC application. Initially for 2 or 4 seconds, cut cut cut noise is not heard in VLC application, However after almost after 5 sec ,I can hear cut cut cut noise in VLC application. With my analysis, hwptr is getting updated properly however I have doubt in app_ptr. I'm attaching the excl sheet with hw_ptr,app_ptr and buf_pos values.
Do the buffer size and period size are set really as expected? Often the driver misses the fact that PCM core doesn't guarantee the alignment of buffer size and period size unless specified explicitly via hw constraints. That is, as default, it's possible to set a buffer size 3000 bytes for the period size 64 bytes. Then the last period is partial.
For aligning the period and the buffer sizes, call snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); in the open callback.
Takashi
How to remove the cut cut cut ... noise in audio ?
Regards, Chakravarthi
On Fri, Aug 3, 2018 at 1:05 PM Takashi Iwai tiwai@suse.de wrote:
On Thu, 02 Aug 2018 16:31:13 +0200, Chakravarthi Pradeep wrote:
I'm working on ALSA driver for PCIe card. My ALSA driver and it's initializing struct snd_pcm_hardware with below parameter.
/************************ code start ************************************************/ static struct snd_pcm_hardware audio_pcm_hardware = { .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_RESUME ), .formats = (SNDRV_PCM_FORMAT_S16_LE | SNDRV_PCM_FORMAT_S24_LE), .rates = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 | SNDRV_PCM_RATE_96000 | SNDRV_PCM_RATE_192000), .rate_min = 44100, .rate_max = 192000, .channels_min = 2, .channels_max = 8, .buffer_bytes_max = 76800, /*75 kbytes */ .period_bytes_min = 512,//4410, /* (channel (2) * sample_rate (44100)
- bit width (24)) / (60 * 8) */
.period_bytes_max = 16*1024, .periods_min = 10, .periods_max = 255,
}; /************************ code end ************************************************/
- I did not understand what is significance of periods_min ,
period_bytes_min , period_bytes_max and periods_max. Can you please tell me what is importance of these parameter and what value should be mentioned according into ALSA.
These three defines the values your hardware may accept: periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
- snd_pcm_ops trigger callback is getting called in the driver when
application sends "start" command. But ALSA driver is stopping by itself after one frame is copied to ALSA framework, without waiting for "stop" command.
For instance: In trigger callback , I'm getting these logs after one frame is copied. Trigger:Start (When Play button is selected/clicked in application, Start command is sent to ALSA driver) Dma transfer is completed. Trigger:Stop. (When Stop button is selected/clicked in application, Stop command is sent to ALSA driver. But stop button is not clicked in this case)
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900 [1.2 <text/html; UTF-8 (quoted-printable)>]
static int uhdc_audio_thread(void *data) { char *audio_frame = NULL; int count = 0; uhdc_t3_card_driver *drv = (uhdc_t3_card_driver *)data; struct snd_pcm_runtime *runtime = drv->substream->runtime;
audio_frame = kmalloc(MAX_AUDIO_SIZE, GFP_DMA); if(!audio_frame) { return -ENOMEM; } while(1) { if (kthread_should_stop()) { dbg_alsa( "###### %s %d\n",__FUNCTION__,__LINE__); break; } dbg_alsa( "###### Waiting for audio signal %s_%d\n",__FUNCTION__,__LINE__); wait_event_interruptible (audio_interrupt, (atomic_read (&audio_data_ready))); atomic_set (&audio_data_ready, 0); g_count = get_audio_size(g_temp_lro); count = g_count; printk( "######audio signal received and audio size:%d runtime->period_size:%d %s_%d\n",g_count,runtime->period_size,__func__,__LINE__); /* dma read is done here */ /* audio_frame contains audio data */ memcpy(drv->substream->runtime->dma_area + drv->buf_pos ,audio_frame,count); /* update the buf_pos */ // here the (auto)increase of buf_pos is handled drv->buf_pos += count; drv->buf_pos %= drv->pcm_buffer_size; printk("\n\n\n hwptr=%d appl=%d pos=%d\n", (int)frames_to_bytes(runtime,runtime->status->hw_ptr),(int)frames_to_bytes(runtime, runtime->control->appl_ptr),drv->buf_pos); /* Below line needs to be uncommented for pointer to be updated in the alsa lib */ snd_pcm_period_elapsed(drv->substream); try_to_freeze(); } kfree(audio_frame); audio_frame = NULL; return 0 ;} [3 hwptr_app_ptr_buf_pos_analysis.xlsx <application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (base64)>]
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
On Mon, 06 Aug 2018 15:23:31 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
I'm sure that I'm calling snd_pcm_period_elapsed() function
You confirmed with putting the debug print, etc?
and my pointer function is given below:
/************************* pointer callback ***************** static snd_pcm_uframes_t uhdc_audio_pcm_pointer(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; uhdc_t3_card_driver *drv = runtime->private_data; return bytes_to_frames(runtime, drv->buf_pos); }
And drv->buf_pos is the correct position that matches with the expected hwptr? Basically there only these two things.
Takashi
Regards, Chakravarthi Pradeep K
On Mon, Aug 6, 2018 at 6:21 PM Takashi Iwai tiwai@suse.de wrote:
On Mon, 06 Aug 2018 14:29:26 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
Thanks for your explanation about period and periods.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause
I'm calling snd_pcm_period_elapsed() in my audio thread snd_pcm_period_elapsed(drv->substream); I'm calling this <snd_pcm_period_elapsed()> function after one frame is copied to from PCIe device. However, hwptr is not updated and no sound in the VLC application.
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
Takashi
Regards, Chakravarthi Pradeep K On Mon, Aug 6, 2018 at 2:09 PM Takashi Iwai tiwai@suse.de wrote:
On Sun, 05 Aug 2018 20:09:47 +0200, Chakravarthi Pradeep wrote:
---------- Forwarded message --------- From: Chakravarthi Pradeep doubleq7@gmail.com Date: Sun 5 Aug, 2018, 14:19 Subject: Re: [alsa-devel] ALSA queries To: tiwai@suse.de
Hello Takashi,
Thanks for your reply.
periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
periods_min = the minimal number of periods : what is meaning of periods , is it minimal number of interrupts ?
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
period_bytes_min = the minimal size of bytes for one period : it means, minimal size of bytes per interrupt in case of device, Is it correct ?
Correct.
what about period_max ?
The maximal number of periods, the counter-part of periods_min.
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
I'm attaching my driver thread along with this mail. Can you please let me know if I have missed something in audio thread. ?. How to make sure in driver that, trigger stop should be called only when stop command is sent from application.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause.
I'm getting cut cut cut ... noise along with audio in VLC application. Initially for 2 or 4 seconds, cut cut cut noise is not heard in VLC application, However after almost after 5 sec ,I can hear cut cut cut noise in VLC application. With my analysis, hwptr is getting updated properly however I have doubt in app_ptr. I'm attaching the excl sheet with hw_ptr,app_ptr and buf_pos values.
Do the buffer size and period size are set really as expected? Often the driver misses the fact that PCM core doesn't guarantee the alignment of buffer size and period size unless specified explicitly via hw constraints. That is, as default, it's possible to set a buffer size 3000 bytes for the period size 64 bytes. Then the last period is partial.
For aligning the period and the buffer sizes, call snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); in the open callback.
Takashi
How to remove the cut cut cut ... noise in audio ?
Regards, Chakravarthi
On Fri, Aug 3, 2018 at 1:05 PM Takashi Iwai tiwai@suse.de wrote:
On Thu, 02 Aug 2018 16:31:13 +0200, Chakravarthi Pradeep wrote: > > I'm working on ALSA driver for PCIe card. My ALSA driver and it's > initializing struct snd_pcm_hardware with below parameter. > > /************************ code start > ************************************************/ > static struct snd_pcm_hardware audio_pcm_hardware = { > .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | > SNDRV_PCM_INFO_MMAP_VALID | > SNDRV_PCM_INFO_BLOCK_TRANSFER | > SNDRV_PCM_INFO_RESUME ), > .formats = (SNDRV_PCM_FORMAT_S16_LE | SNDRV_PCM_FORMAT_S24_LE), > .rates = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 | > SNDRV_PCM_RATE_96000 | SNDRV_PCM_RATE_192000), > .rate_min = 44100, > .rate_max = 192000, > .channels_min = 2, > .channels_max = 8, > .buffer_bytes_max = 76800, /*75 kbytes */ > .period_bytes_min = 512,//4410, /* (channel (2) * sample_rate (44100) > * bit width (24)) / (60 * 8) */ > .period_bytes_max = 16*1024, > .periods_min = 10, > .periods_max = 255, > > }; > /************************ code end > ************************************************/ > > 1) I did not understand what is significance of periods_min , > period_bytes_min , period_bytes_max and periods_max. Can you please > tell me what is importance of these parameter and what value should be > mentioned according into ALSA.
These three defines the values your hardware may accept: periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
> 2) snd_pcm_ops trigger callback is getting called in the driver when > application sends "start" command. But ALSA driver is stopping by > itself after one frame is copied to ALSA framework, without waiting > for "stop" command. > > For instance: > In trigger callback , I'm getting these logs after one frame is copied. > Trigger:Start (When Play button is selected/clicked in application, > Start command is sent to ALSA driver) > Dma transfer is completed. > Trigger:Stop. (When Stop button is selected/clicked in application, > Stop command is sent to ALSA driver. But stop button is not clicked in > this case)
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900 [1.2 <text/html; UTF-8 (quoted-printable)>]
static int uhdc_audio_thread(void *data) { char *audio_frame = NULL; int count = 0; uhdc_t3_card_driver *drv = (uhdc_t3_card_driver *)data; struct snd_pcm_runtime *runtime = drv->substream->runtime;
audio_frame = kmalloc(MAX_AUDIO_SIZE, GFP_DMA); if(!audio_frame) { return -ENOMEM; } while(1) { if (kthread_should_stop()) { dbg_alsa( "###### %s %d\n",__FUNCTION__,__LINE__); break; } dbg_alsa( "###### Waiting for audio signal %s_%d\n",__FUNCTION__,__LINE__); wait_event_interruptible (audio_interrupt, (atomic_read (&audio_data_ready))); atomic_set (&audio_data_ready, 0); g_count = get_audio_size(g_temp_lro); count = g_count; printk( "######audio signal received and audio size:%d runtime->period_size:%d %s_%d\n",g_count,runtime->period_size,__func__,__LINE__); /* dma read is done here */ /* audio_frame contains audio data */ memcpy(drv->substream->runtime->dma_area + drv->buf_pos ,audio_frame,count); /* update the buf_pos */ // here the (auto)increase of buf_pos is handled drv->buf_pos += count; drv->buf_pos %= drv->pcm_buffer_size; printk("\n\n\n hwptr=%d appl=%d pos=%d\n", (int)frames_to_bytes(runtime,runtime->status->hw_ptr),(int)frames_to_bytes(runtime, runtime->control->appl_ptr),drv->buf_pos); /* Below line needs to be uncommented for pointer to be updated in the alsa lib */ snd_pcm_period_elapsed(drv->substream); try_to_freeze(); } kfree(audio_frame); audio_frame = NULL; return 0 ;} [3 hwptr_app_ptr_buf_pos_analysis.xlsx <application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (base64)>]
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
Hello Takashi,
You confirmed with putting the debug print, etc?
Yes, its confirmed.
And drv->buf_pos is the correct position that matches with the expected hwptr? Basically there only these two things.
If DMA size per interrupt is of 4K bytes then drv->buf_pos is updated with 4K bytes in audio thread. However the same being updated in pointer call back also.
From the debug log , sometimes pointer callback is not getting called
and hwptr is zero at this point. When hwptr is zero then no audio in VLC application. Why pointer call back is not gettting called ?
Regards, Chakravarthi Pradeep K On Mon, Aug 6, 2018 at 7:02 PM Takashi Iwai tiwai@suse.de wrote:
On Mon, 06 Aug 2018 15:23:31 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
I'm sure that I'm calling snd_pcm_period_elapsed() function
You confirmed with putting the debug print, etc?
and my pointer function is given below:
/************************* pointer callback ***************** static snd_pcm_uframes_t uhdc_audio_pcm_pointer(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; uhdc_t3_card_driver *drv = runtime->private_data; return bytes_to_frames(runtime, drv->buf_pos); }
And drv->buf_pos is the correct position that matches with the expected hwptr? Basically there only these two things.
Takashi
Regards, Chakravarthi Pradeep K
On Mon, Aug 6, 2018 at 6:21 PM Takashi Iwai tiwai@suse.de wrote:
On Mon, 06 Aug 2018 14:29:26 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
Thanks for your explanation about period and periods.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause
I'm calling snd_pcm_period_elapsed() in my audio thread snd_pcm_period_elapsed(drv->substream); I'm calling this <snd_pcm_period_elapsed()> function after one frame is copied to from PCIe device. However, hwptr is not updated and no sound in the VLC application.
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
Takashi
Regards, Chakravarthi Pradeep K On Mon, Aug 6, 2018 at 2:09 PM Takashi Iwai tiwai@suse.de wrote:
On Sun, 05 Aug 2018 20:09:47 +0200, Chakravarthi Pradeep wrote:
---------- Forwarded message --------- From: Chakravarthi Pradeep doubleq7@gmail.com Date: Sun 5 Aug, 2018, 14:19 Subject: Re: [alsa-devel] ALSA queries To: tiwai@suse.de
Hello Takashi,
Thanks for your reply.
periods_min = the minimal number of periods period_bytes_min = the minimal size of bytes for one period period_bytes_max = the maximal size of bytes for one period
periods_min = the minimal number of periods : what is meaning of periods , is it minimal number of interrupts ?
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
period_bytes_min = the minimal size of bytes for one period : it means, minimal size of bytes per interrupt in case of device, Is it correct ?
Correct.
what about period_max ?
The maximal number of periods, the counter-part of periods_min.
It's most likely the ALSA PCM core's safety stop; your driver seem to have missed snd_pcm_period_elapsed() calls, so the hwptr isn't updated, resulting in XRUN. ALSA PCM core checks such XRUN condition with the own timer.
I'm attaching my driver thread along with this mail. Can you please let me know if I have missed something in audio thread. ?. How to make sure in driver that, trigger stop should be called only when stop command is sent from application.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause.
I'm getting cut cut cut ... noise along with audio in VLC application. Initially for 2 or 4 seconds, cut cut cut noise is not heard in VLC application, However after almost after 5 sec ,I can hear cut cut cut noise in VLC application. With my analysis, hwptr is getting updated properly however I have doubt in app_ptr. I'm attaching the excl sheet with hw_ptr,app_ptr and buf_pos values.
Do the buffer size and period size are set really as expected? Often the driver misses the fact that PCM core doesn't guarantee the alignment of buffer size and period size unless specified explicitly via hw constraints. That is, as default, it's possible to set a buffer size 3000 bytes for the period size 64 bytes. Then the last period is partial.
For aligning the period and the buffer sizes, call snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); in the open callback.
Takashi
How to remove the cut cut cut ... noise in audio ?
Regards, Chakravarthi
On Fri, Aug 3, 2018 at 1:05 PM Takashi Iwai tiwai@suse.de wrote: > > On Thu, 02 Aug 2018 16:31:13 +0200, > Chakravarthi Pradeep wrote: > > > > I'm working on ALSA driver for PCIe card. My ALSA driver and it's > > initializing struct snd_pcm_hardware with below parameter. > > > > /************************ code start > > ************************************************/ > > static struct snd_pcm_hardware audio_pcm_hardware = { > > .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | > > SNDRV_PCM_INFO_MMAP_VALID | > > SNDRV_PCM_INFO_BLOCK_TRANSFER | > > SNDRV_PCM_INFO_RESUME ), > > .formats = (SNDRV_PCM_FORMAT_S16_LE | SNDRV_PCM_FORMAT_S24_LE), > > .rates = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 | > > SNDRV_PCM_RATE_96000 | SNDRV_PCM_RATE_192000), > > .rate_min = 44100, > > .rate_max = 192000, > > .channels_min = 2, > > .channels_max = 8, > > .buffer_bytes_max = 76800, /*75 kbytes */ > > .period_bytes_min = 512,//4410, /* (channel (2) * sample_rate (44100) > > * bit width (24)) / (60 * 8) */ > > .period_bytes_max = 16*1024, > > .periods_min = 10, > > .periods_max = 255, > > > > }; > > /************************ code end > > ************************************************/ > > > > 1) I did not understand what is significance of periods_min , > > period_bytes_min , period_bytes_max and periods_max. Can you please > > tell me what is importance of these parameter and what value should be > > mentioned according into ALSA. > > These three defines the values your hardware may accept: > periods_min = the minimal number of periods > period_bytes_min = the minimal size of bytes for one period > period_bytes_max = the maximal size of bytes for one period > > > 2) snd_pcm_ops trigger callback is getting called in the driver when > > application sends "start" command. But ALSA driver is stopping by > > itself after one frame is copied to ALSA framework, without waiting > > for "stop" command. > > > > For instance: > > In trigger callback , I'm getting these logs after one frame is copied. > > Trigger:Start (When Play button is selected/clicked in application, > > Start command is sent to ALSA driver) > > Dma transfer is completed. > > Trigger:Stop. (When Stop button is selected/clicked in application, > > Stop command is sent to ALSA driver. But stop button is not clicked in > > this case) > > It's most likely the ALSA PCM core's safety stop; your driver seem to > have missed snd_pcm_period_elapsed() calls, so the hwptr isn't > updated, resulting in XRUN. ALSA PCM core checks such XRUN condition > with the own timer. > > > Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900 [1.2 <text/html; UTF-8 (quoted-printable)>]
static int uhdc_audio_thread(void *data) { char *audio_frame = NULL; int count = 0; uhdc_t3_card_driver *drv = (uhdc_t3_card_driver *)data; struct snd_pcm_runtime *runtime = drv->substream->runtime;
audio_frame = kmalloc(MAX_AUDIO_SIZE, GFP_DMA); if(!audio_frame) { return -ENOMEM; } while(1) { if (kthread_should_stop()) { dbg_alsa( "###### %s %d\n",__FUNCTION__,__LINE__); break; } dbg_alsa( "###### Waiting for audio signal %s_%d\n",__FUNCTION__,__LINE__); wait_event_interruptible (audio_interrupt, (atomic_read (&audio_data_ready))); atomic_set (&audio_data_ready, 0); g_count = get_audio_size(g_temp_lro); count = g_count; printk( "######audio signal received and audio size:%d runtime->period_size:%d %s_%d\n",g_count,runtime->period_size,__func__,__LINE__); /* dma read is done here */ /* audio_frame contains audio data */ memcpy(drv->substream->runtime->dma_area + drv->buf_pos ,audio_frame,count); /* update the buf_pos */ // here the (auto)increase of buf_pos is handled drv->buf_pos += count; drv->buf_pos %= drv->pcm_buffer_size; printk("\n\n\n hwptr=%d appl=%d pos=%d\n", (int)frames_to_bytes(runtime,runtime->status->hw_ptr),(int)frames_to_bytes(runtime, runtime->control->appl_ptr),drv->buf_pos); /* Below line needs to be uncommented for pointer to be updated in the alsa lib */ snd_pcm_period_elapsed(drv->substream); try_to_freeze(); } kfree(audio_frame); audio_frame = NULL; return 0 ;} [3 hwptr_app_ptr_buf_pos_analysis.xlsx <application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (base64)>]
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
On Mon, 06 Aug 2018 17:24:49 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
You confirmed with putting the debug print, etc?
Yes, its confirmed.
And drv->buf_pos is the correct position that matches with the expected hwptr? Basically there only these two things.
If DMA size per interrupt is of 4K bytes then drv->buf_pos is updated with 4K bytes in audio thread. However the same being updated in pointer call back also.
From the debug log , sometimes pointer callback is not getting called and hwptr is zero at this point. When hwptr is zero then no audio in VLC application. Why pointer call back is not gettting called ?
If the pointer callback isn't called from snd_pcm_period_elapsed(), the only reason would be that the stream isn't in the running state, which is already inconsistent for the condition to call snd_pcm_period_elapsed(). Otherwise it calls snd_pcm_update_hw_ptr0() and there the pointer callback gets called unconditionally.
So, either the measurement is wrong, or the stream is already screwed up at the time you call snd_pcm_period_elapsed().
Again, snd_pcm_period_elapsed() itself calls the pointer callback, hence the driver must know the exact position at that timing. If you're using a multi threading, make sure that the updated pointer has been already propagated at snd_pcm_period_elapsed() is called in another thread, for example.
Takashi
Regards, Chakravarthi Pradeep K On Mon, Aug 6, 2018 at 7:02 PM Takashi Iwai tiwai@suse.de wrote:
On Mon, 06 Aug 2018 15:23:31 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
I'm sure that I'm calling snd_pcm_period_elapsed() function
You confirmed with putting the debug print, etc?
and my pointer function is given below:
/************************* pointer callback ***************** static snd_pcm_uframes_t uhdc_audio_pcm_pointer(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; uhdc_t3_card_driver *drv = runtime->private_data; return bytes_to_frames(runtime, drv->buf_pos); }
And drv->buf_pos is the correct position that matches with the expected hwptr? Basically there only these two things.
Takashi
Regards, Chakravarthi Pradeep K
On Mon, Aug 6, 2018 at 6:21 PM Takashi Iwai tiwai@suse.de wrote:
On Mon, 06 Aug 2018 14:29:26 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
Thanks for your explanation about period and periods.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause
I'm calling snd_pcm_period_elapsed() in my audio thread snd_pcm_period_elapsed(drv->substream); I'm calling this <snd_pcm_period_elapsed()> function after one frame is copied to from PCIe device. However, hwptr is not updated and no sound in the VLC application.
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
Takashi
Regards, Chakravarthi Pradeep K On Mon, Aug 6, 2018 at 2:09 PM Takashi Iwai tiwai@suse.de wrote:
On Sun, 05 Aug 2018 20:09:47 +0200, Chakravarthi Pradeep wrote: > > ---------- Forwarded message --------- > From: Chakravarthi Pradeep doubleq7@gmail.com > Date: Sun 5 Aug, 2018, 14:19 > Subject: Re: [alsa-devel] ALSA queries > To: tiwai@suse.de > > > Hello Takashi, > > Thanks for your reply. > > periods_min = the minimal number of periods > period_bytes_min = the minimal size of bytes for one period > period_bytes_max = the maximal size of bytes for one period > > > periods_min = the minimal number of periods : what is meaning of > periods , is it minimal number of interrupts ?
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
> period_bytes_min = the minimal size of bytes for one period : it > means, minimal size of bytes per interrupt in case of device, Is it > correct ?
Correct.
> what about period_max ?
The maximal number of periods, the counter-part of periods_min.
> It's most likely the ALSA PCM core's safety stop; your driver seem to > have missed snd_pcm_period_elapsed() calls, so the hwptr isn't > updated, resulting in XRUN. ALSA PCM core checks such XRUN condition > with the own timer. > > I'm attaching my driver thread along with this mail. Can you please > let me know if I have missed something in audio thread. ?. How to make > sure in driver that, trigger stop should be called only when stop > command is sent from application.
Erm, I'm no consultant. Does your driver issue really snd_pcm_period_elapsed() or not? You should know that.
If the problem happens even if the driver really calls snd_pcm_period_elapsed(), then it's another cause.
> I'm getting cut cut cut ... noise along with audio in VLC application. > Initially for 2 or 4 seconds, cut cut cut noise is not heard in VLC > application, However after almost after 5 sec ,I can hear cut cut cut > noise in VLC application. With my analysis, hwptr is getting updated > properly however I have doubt in app_ptr. I'm attaching the excl sheet > with hw_ptr,app_ptr and buf_pos values.
Do the buffer size and period size are set really as expected? Often the driver misses the fact that PCM core doesn't guarantee the alignment of buffer size and period size unless specified explicitly via hw constraints. That is, as default, it's possible to set a buffer size 3000 bytes for the period size 64 bytes. Then the last period is partial.
For aligning the period and the buffer sizes, call snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); in the open callback.
Takashi
> > How to remove the cut cut cut ... noise in audio ? > > Regards, > Chakravarthi > > On Fri, Aug 3, 2018 at 1:05 PM Takashi Iwai tiwai@suse.de wrote: > > > > On Thu, 02 Aug 2018 16:31:13 +0200, > > Chakravarthi Pradeep wrote: > > > > > > I'm working on ALSA driver for PCIe card. My ALSA driver and it's > > > initializing struct snd_pcm_hardware with below parameter. > > > > > > /************************ code start > > > ************************************************/ > > > static struct snd_pcm_hardware audio_pcm_hardware = { > > > .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | > > > SNDRV_PCM_INFO_MMAP_VALID | > > > SNDRV_PCM_INFO_BLOCK_TRANSFER | > > > SNDRV_PCM_INFO_RESUME ), > > > .formats = (SNDRV_PCM_FORMAT_S16_LE | SNDRV_PCM_FORMAT_S24_LE), > > > .rates = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 | > > > SNDRV_PCM_RATE_96000 | SNDRV_PCM_RATE_192000), > > > .rate_min = 44100, > > > .rate_max = 192000, > > > .channels_min = 2, > > > .channels_max = 8, > > > .buffer_bytes_max = 76800, /*75 kbytes */ > > > .period_bytes_min = 512,//4410, /* (channel (2) * sample_rate (44100) > > > * bit width (24)) / (60 * 8) */ > > > .period_bytes_max = 16*1024, > > > .periods_min = 10, > > > .periods_max = 255, > > > > > > }; > > > /************************ code end > > > ************************************************/ > > > > > > 1) I did not understand what is significance of periods_min , > > > period_bytes_min , period_bytes_max and periods_max. Can you please > > > tell me what is importance of these parameter and what value should be > > > mentioned according into ALSA. > > > > These three defines the values your hardware may accept: > > periods_min = the minimal number of periods > > period_bytes_min = the minimal size of bytes for one period > > period_bytes_max = the maximal size of bytes for one period > > > > > 2) snd_pcm_ops trigger callback is getting called in the driver when > > > application sends "start" command. But ALSA driver is stopping by > > > itself after one frame is copied to ALSA framework, without waiting > > > for "stop" command. > > > > > > For instance: > > > In trigger callback , I'm getting these logs after one frame is copied. > > > Trigger:Start (When Play button is selected/clicked in application, > > > Start command is sent to ALSA driver) > > > Dma transfer is completed. > > > Trigger:Stop. (When Stop button is selected/clicked in application, > > > Stop command is sent to ALSA driver. But stop button is not clicked in > > > this case) > > > > It's most likely the ALSA PCM core's safety stop; your driver seem to > > have missed snd_pcm_period_elapsed() calls, so the hwptr isn't > > updated, resulting in XRUN. ALSA PCM core checks such XRUN condition > > with the own timer. > > > > > > Takashi > > > > -- > Thanks and Regards > Chakravarthi Pradeep.K > Ph: 91 9980434900 > [1.2 <text/html; UTF-8 (quoted-printable)>] > > static int uhdc_audio_thread(void *data) > { > char *audio_frame = NULL; > int count = 0; > uhdc_t3_card_driver *drv = (uhdc_t3_card_driver *)data; > struct snd_pcm_runtime *runtime = drv->substream->runtime; > > > audio_frame = kmalloc(MAX_AUDIO_SIZE, GFP_DMA); > if(!audio_frame) > { > return -ENOMEM; > } > while(1) > { > > if (kthread_should_stop()) > { > dbg_alsa( "###### %s %d\n",__FUNCTION__,__LINE__); > break; > } > dbg_alsa( "###### Waiting for audio signal %s_%d\n",__FUNCTION__,__LINE__); > wait_event_interruptible (audio_interrupt, (atomic_read (&audio_data_ready))); > atomic_set (&audio_data_ready, 0); > g_count = get_audio_size(g_temp_lro); > count = g_count; > printk( "######audio signal received and audio size:%d runtime->period_size:%d %s_%d\n",g_count,runtime->period_size,__func__,__LINE__); > > /* dma read is done here */ > /* audio_frame contains audio data */ > memcpy(drv->substream->runtime->dma_area + drv->buf_pos ,audio_frame,count); > > /* update the buf_pos */ > // here the (auto)increase of buf_pos is handled > drv->buf_pos += count; > drv->buf_pos %= drv->pcm_buffer_size; > > > printk("\n\n\n hwptr=%d appl=%d pos=%d\n", > (int)frames_to_bytes(runtime,runtime->status->hw_ptr),(int)frames_to_bytes(runtime, runtime->control->appl_ptr),drv->buf_pos); > /* Below line needs to be uncommented for pointer to be updated in the alsa lib */ > snd_pcm_period_elapsed(drv->substream); > > try_to_freeze(); > > } > > kfree(audio_frame); > audio_frame = NULL; > > return 0 ; > > } > [3 hwptr_app_ptr_buf_pos_analysis.xlsx <application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (base64)>] >
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
Dear Takashi,
Trigger stop is getting called , because of this hwptr is zero and pointer call back is not getting called. Below is my log from driver.
[ 838.491681] Trigger:Start [ 839.522233] hwptr=0 buf_pos:3456 [ 839.522244] buf_pos :3456 bytes_to_frames:864 uhdc_audio_pcm_pointer_253 [ 839.522249] Trigger:Stop
In normal scenario, Trigger stop is not getting called and audio was able to render in the VLC application. Below log for normal scenario, [ 802.785893] Trigger:Start [ 814.288309] hwptr=0 buf_pos:6272 [ 814.288323] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288362] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288378] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.305079] hwptr=6272 buf_pos:9472 [ 814.305091] buf_pos :9472 bytes_to_frames:2368 uhdc_audio_pcm_pointer_253 [ 814.321741] hwptr=9472 buf_pos:12672 [ 814.321748] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321777] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321785] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.338452] hwptr=12672 buf_pos:15872 [ 814.338459] buf_pos :15872 bytes_to_frames:3968 uhdc_audio_pcm_pointer_253 [ 814.355242] hwptr=15872 buf_pos:19072 [ 814.355248] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355288] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355294] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.371822] hwptr=19072 buf_pos:22272 ... ... [ 830.739031] Trigger:Stop
I can not do rmmod for ALSA driver. If I do sudo rmmod mydriver then it says "rmmod: ERROR: Module mydriver is in use"
How can I remove mydriver module from linux kernel ?
Regards, Chakravarthi Pradeep
On Mon, Aug 6, 2018 at 9:00 PM Takashi Iwai tiwai@suse.de wrote:
On Mon, 06 Aug 2018 17:24:49 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
You confirmed with putting the debug print, etc?
Yes, its confirmed.
And drv->buf_pos is the correct position that matches with the expected hwptr? Basically there only these two things.
If DMA size per interrupt is of 4K bytes then drv->buf_pos is updated with 4K bytes in audio thread. However the same being updated in pointer call back also.
From the debug log , sometimes pointer callback is not getting called and hwptr is zero at this point. When hwptr is zero then no audio in VLC application. Why pointer call back is not gettting called ?
If the pointer callback isn't called from snd_pcm_period_elapsed(), the only reason would be that the stream isn't in the running state, which is already inconsistent for the condition to call snd_pcm_period_elapsed(). Otherwise it calls snd_pcm_update_hw_ptr0() and there the pointer callback gets called unconditionally.
So, either the measurement is wrong, or the stream is already screwed up at the time you call snd_pcm_period_elapsed().
Again, snd_pcm_period_elapsed() itself calls the pointer callback, hence the driver must know the exact position at that timing. If you're using a multi threading, make sure that the updated pointer has been already propagated at snd_pcm_period_elapsed() is called in another thread, for example.
Takashi
Regards, Chakravarthi Pradeep K On Mon, Aug 6, 2018 at 7:02 PM Takashi Iwai tiwai@suse.de wrote:
On Mon, 06 Aug 2018 15:23:31 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
I'm sure that I'm calling snd_pcm_period_elapsed() function
You confirmed with putting the debug print, etc?
and my pointer function is given below:
/************************* pointer callback ***************** static snd_pcm_uframes_t uhdc_audio_pcm_pointer(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; uhdc_t3_card_driver *drv = runtime->private_data; return bytes_to_frames(runtime, drv->buf_pos); }
And drv->buf_pos is the correct position that matches with the expected hwptr? Basically there only these two things.
Takashi
Regards, Chakravarthi Pradeep K
On Mon, Aug 6, 2018 at 6:21 PM Takashi Iwai tiwai@suse.de wrote:
On Mon, 06 Aug 2018 14:29:26 +0200, Chakravarthi Pradeep wrote:
Hello Takashi,
Thanks for your explanation about period and periods.
> Erm, I'm no consultant. Does your driver issue really > snd_pcm_period_elapsed() or not? You should know that. > > If the problem happens even if the driver really calls > snd_pcm_period_elapsed(), then it's another cause
I'm calling snd_pcm_period_elapsed() in my audio thread snd_pcm_period_elapsed(drv->substream); I'm calling this <snd_pcm_period_elapsed()> function after one frame is copied to from PCIe device. However, hwptr is not updated and no sound in the VLC application.
OK, so you are sure that the function is really called, not only in theory, right? Then the next item to check is the pointer callback. The hwptr is updated based on the value returned from this callback.
Takashi
Regards, Chakravarthi Pradeep K On Mon, Aug 6, 2018 at 2:09 PM Takashi Iwai tiwai@suse.de wrote: > > On Sun, 05 Aug 2018 20:09:47 +0200, > Chakravarthi Pradeep wrote: > > > > ---------- Forwarded message --------- > > From: Chakravarthi Pradeep doubleq7@gmail.com > > Date: Sun 5 Aug, 2018, 14:19 > > Subject: Re: [alsa-devel] ALSA queries > > To: tiwai@suse.de > > > > > > Hello Takashi, > > > > Thanks for your reply. > > > > periods_min = the minimal number of periods > > period_bytes_min = the minimal size of bytes for one period > > period_bytes_max = the maximal size of bytes for one period > > > > > > periods_min = the minimal number of periods : what is meaning of > > periods , is it minimal number of interrupts ? > > The "period" in ALSA PCM definition represents the interval time (or > frames) of the periodical interrupts on the ring buffer. If the irq > is issued for each 256 frames while the ring buffer size is 1024 > frames, periods = 1024/256 = 4. The periods_min defines the minimal > number of periods the hardware may accept. > > > period_bytes_min = the minimal size of bytes for one period : it > > means, minimal size of bytes per interrupt in case of device, Is it > > correct ? > > Correct. > > > what about period_max ? > > The maximal number of periods, the counter-part of periods_min. > > > > It's most likely the ALSA PCM core's safety stop; your driver seem to > > have missed snd_pcm_period_elapsed() calls, so the hwptr isn't > > updated, resulting in XRUN. ALSA PCM core checks such XRUN condition > > with the own timer. > > > > I'm attaching my driver thread along with this mail. Can you please > > let me know if I have missed something in audio thread. ?. How to make > > sure in driver that, trigger stop should be called only when stop > > command is sent from application. > > Erm, I'm no consultant. Does your driver issue really > snd_pcm_period_elapsed() or not? You should know that. > > If the problem happens even if the driver really calls > snd_pcm_period_elapsed(), then it's another cause. > > > I'm getting cut cut cut ... noise along with audio in VLC application. > > Initially for 2 or 4 seconds, cut cut cut noise is not heard in VLC > > application, However after almost after 5 sec ,I can hear cut cut cut > > noise in VLC application. With my analysis, hwptr is getting updated > > properly however I have doubt in app_ptr. I'm attaching the excl sheet > > with hw_ptr,app_ptr and buf_pos values. > > Do the buffer size and period size are set really as expected? > Often the driver misses the fact that PCM core doesn't guarantee the > alignment of buffer size and period size unless specified explicitly > via hw constraints. That is, as default, it's possible to set a > buffer size 3000 bytes for the period size 64 bytes. Then the last > period is partial. > > For aligning the period and the buffer sizes, call > snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); > in the open callback. > > > Takashi > > > > > How to remove the cut cut cut ... noise in audio ? > > > > Regards, > > Chakravarthi > > > > On Fri, Aug 3, 2018 at 1:05 PM Takashi Iwai tiwai@suse.de wrote: > > > > > > On Thu, 02 Aug 2018 16:31:13 +0200, > > > Chakravarthi Pradeep wrote: > > > > > > > > I'm working on ALSA driver for PCIe card. My ALSA driver and it's > > > > initializing struct snd_pcm_hardware with below parameter. > > > > > > > > /************************ code start > > > > ************************************************/ > > > > static struct snd_pcm_hardware audio_pcm_hardware = { > > > > .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | > > > > SNDRV_PCM_INFO_MMAP_VALID | > > > > SNDRV_PCM_INFO_BLOCK_TRANSFER | > > > > SNDRV_PCM_INFO_RESUME ), > > > > .formats = (SNDRV_PCM_FORMAT_S16_LE | SNDRV_PCM_FORMAT_S24_LE), > > > > .rates = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 | > > > > SNDRV_PCM_RATE_96000 | SNDRV_PCM_RATE_192000), > > > > .rate_min = 44100, > > > > .rate_max = 192000, > > > > .channels_min = 2, > > > > .channels_max = 8, > > > > .buffer_bytes_max = 76800, /*75 kbytes */ > > > > .period_bytes_min = 512,//4410, /* (channel (2) * sample_rate (44100) > > > > * bit width (24)) / (60 * 8) */ > > > > .period_bytes_max = 16*1024, > > > > .periods_min = 10, > > > > .periods_max = 255, > > > > > > > > }; > > > > /************************ code end > > > > ************************************************/ > > > > > > > > 1) I did not understand what is significance of periods_min , > > > > period_bytes_min , period_bytes_max and periods_max. Can you please > > > > tell me what is importance of these parameter and what value should be > > > > mentioned according into ALSA. > > > > > > These three defines the values your hardware may accept: > > > periods_min = the minimal number of periods > > > period_bytes_min = the minimal size of bytes for one period > > > period_bytes_max = the maximal size of bytes for one period > > > > > > > 2) snd_pcm_ops trigger callback is getting called in the driver when > > > > application sends "start" command. But ALSA driver is stopping by > > > > itself after one frame is copied to ALSA framework, without waiting > > > > for "stop" command. > > > > > > > > For instance: > > > > In trigger callback , I'm getting these logs after one frame is copied. > > > > Trigger:Start (When Play button is selected/clicked in application, > > > > Start command is sent to ALSA driver) > > > > Dma transfer is completed. > > > > Trigger:Stop. (When Stop button is selected/clicked in application, > > > > Stop command is sent to ALSA driver. But stop button is not clicked in > > > > this case) > > > > > > It's most likely the ALSA PCM core's safety stop; your driver seem to > > > have missed snd_pcm_period_elapsed() calls, so the hwptr isn't > > > updated, resulting in XRUN. ALSA PCM core checks such XRUN condition > > > with the own timer. > > > > > > > > > Takashi > > > > > > > > -- > > Thanks and Regards > > Chakravarthi Pradeep.K > > Ph: 91 9980434900 > > [1.2 <text/html; UTF-8 (quoted-printable)>] > > > > static int uhdc_audio_thread(void *data) > > { > > char *audio_frame = NULL; > > int count = 0; > > uhdc_t3_card_driver *drv = (uhdc_t3_card_driver *)data; > > struct snd_pcm_runtime *runtime = drv->substream->runtime; > > > > > > audio_frame = kmalloc(MAX_AUDIO_SIZE, GFP_DMA); > > if(!audio_frame) > > { > > return -ENOMEM; > > } > > while(1) > > { > > > > if (kthread_should_stop()) > > { > > dbg_alsa( "###### %s %d\n",__FUNCTION__,__LINE__); > > break; > > } > > dbg_alsa( "###### Waiting for audio signal %s_%d\n",__FUNCTION__,__LINE__); > > wait_event_interruptible (audio_interrupt, (atomic_read (&audio_data_ready))); > > atomic_set (&audio_data_ready, 0); > > g_count = get_audio_size(g_temp_lro); > > count = g_count; > > printk( "######audio signal received and audio size:%d runtime->period_size:%d %s_%d\n",g_count,runtime->period_size,__func__,__LINE__); > > > > /* dma read is done here */ > > /* audio_frame contains audio data */ > > memcpy(drv->substream->runtime->dma_area + drv->buf_pos ,audio_frame,count); > > > > /* update the buf_pos */ > > // here the (auto)increase of buf_pos is handled > > drv->buf_pos += count; > > drv->buf_pos %= drv->pcm_buffer_size; > > > > > > printk("\n\n\n hwptr=%d appl=%d pos=%d\n", > > (int)frames_to_bytes(runtime,runtime->status->hw_ptr),(int)frames_to_bytes(runtime, runtime->control->appl_ptr),drv->buf_pos); > > /* Below line needs to be uncommented for pointer to be updated in the alsa lib */ > > snd_pcm_period_elapsed(drv->substream); > > > > try_to_freeze(); > > > > } > > > > kfree(audio_frame); > > audio_frame = NULL; > > > > return 0 ; > > > > } > > [3 hwptr_app_ptr_buf_pos_analysis.xlsx <application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (base64)>] > >
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
On Tue, 07 Aug 2018 13:59:46 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Trigger stop is getting called , because of this hwptr is zero and pointer call back is not getting called. Below is my log from driver.
[ 838.491681] Trigger:Start [ 839.522233] hwptr=0 buf_pos:3456 [ 839.522244] buf_pos :3456 bytes_to_frames:864 uhdc_audio_pcm_pointer_253 [ 839.522249] Trigger:Stop
Then you need to figure out the code path of the trigger stop.
In normal scenario, Trigger stop is not getting called and audio was able to render in the VLC application. Below log for normal scenario, [ 802.785893] Trigger:Start [ 814.288309] hwptr=0 buf_pos:6272 [ 814.288323] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288362] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288378] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.305079] hwptr=6272 buf_pos:9472 [ 814.305091] buf_pos :9472 bytes_to_frames:2368 uhdc_audio_pcm_pointer_253 [ 814.321741] hwptr=9472 buf_pos:12672 [ 814.321748] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321777] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321785] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.338452] hwptr=12672 buf_pos:15872 [ 814.338459] buf_pos :15872 bytes_to_frames:3968 uhdc_audio_pcm_pointer_253 [ 814.355242] hwptr=15872 buf_pos:19072 [ 814.355248] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355288] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355294] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.371822] hwptr=19072 buf_pos:22272 ... ... [ 830.739031] Trigger:Stop
I can not do rmmod for ALSA driver. If I do sudo rmmod mydriver then it says "rmmod: ERROR: Module mydriver is in use"
How can I remove mydriver module from linux kernel ?
Likely some program is using the sound device. For example, a mixer applet or PulseAudio keeps opening the control device. Check it via "fuser -v /dev/snd/*"
Takashi
Dear Takashi,
In previous mail you have mentioned
So, either the measurement is wrong, or the stream is already screwed up at the time you call snd_pcm_period_elapsed().
what it means "measurement is wrong" and how to make that measurement is correct ?
Regards, Chakravarthi On Tue, Aug 7, 2018 at 5:33 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 13:59:46 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Trigger stop is getting called , because of this hwptr is zero and pointer call back is not getting called. Below is my log from driver.
[ 838.491681] Trigger:Start [ 839.522233] hwptr=0 buf_pos:3456 [ 839.522244] buf_pos :3456 bytes_to_frames:864 uhdc_audio_pcm_pointer_253 [ 839.522249] Trigger:Stop
Then you need to figure out the code path of the trigger stop.
In normal scenario, Trigger stop is not getting called and audio was able to render in the VLC application. Below log for normal scenario, [ 802.785893] Trigger:Start [ 814.288309] hwptr=0 buf_pos:6272 [ 814.288323] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288362] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288378] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.305079] hwptr=6272 buf_pos:9472 [ 814.305091] buf_pos :9472 bytes_to_frames:2368 uhdc_audio_pcm_pointer_253 [ 814.321741] hwptr=9472 buf_pos:12672 [ 814.321748] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321777] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321785] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.338452] hwptr=12672 buf_pos:15872 [ 814.338459] buf_pos :15872 bytes_to_frames:3968 uhdc_audio_pcm_pointer_253 [ 814.355242] hwptr=15872 buf_pos:19072 [ 814.355248] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355288] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355294] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.371822] hwptr=19072 buf_pos:22272 ... ... [ 830.739031] Trigger:Stop
I can not do rmmod for ALSA driver. If I do sudo rmmod mydriver then it says "rmmod: ERROR: Module mydriver is in use"
How can I remove mydriver module from linux kernel ?
Likely some program is using the sound device. For example, a mixer applet or PulseAudio keeps opening the control device. Check it via "fuser -v /dev/snd/*"
Takashi
On Tue, 07 Aug 2018 14:08:05 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
In previous mail you have mentioned
So, either the measurement is wrong, or the stream is already screwed up at the time you call snd_pcm_period_elapsed().
what it means "measurement is wrong" and how to make that measurement is correct ?
See what I wrote: "either". I can't exclude the possibility that you are measuring the code calls incorrectly, of course. This is one case. Another case would be the incorrect state that is already screwed up at the time of snd_pcm_period_elapsed() call.
Takashi
Regards, Chakravarthi On Tue, Aug 7, 2018 at 5:33 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 13:59:46 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Trigger stop is getting called , because of this hwptr is zero and pointer call back is not getting called. Below is my log from driver.
[ 838.491681] Trigger:Start [ 839.522233] hwptr=0 buf_pos:3456 [ 839.522244] buf_pos :3456 bytes_to_frames:864 uhdc_audio_pcm_pointer_253 [ 839.522249] Trigger:Stop
Then you need to figure out the code path of the trigger stop.
In normal scenario, Trigger stop is not getting called and audio was able to render in the VLC application. Below log for normal scenario, [ 802.785893] Trigger:Start [ 814.288309] hwptr=0 buf_pos:6272 [ 814.288323] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288362] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288378] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.305079] hwptr=6272 buf_pos:9472 [ 814.305091] buf_pos :9472 bytes_to_frames:2368 uhdc_audio_pcm_pointer_253 [ 814.321741] hwptr=9472 buf_pos:12672 [ 814.321748] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321777] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321785] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.338452] hwptr=12672 buf_pos:15872 [ 814.338459] buf_pos :15872 bytes_to_frames:3968 uhdc_audio_pcm_pointer_253 [ 814.355242] hwptr=15872 buf_pos:19072 [ 814.355248] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355288] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355294] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.371822] hwptr=19072 buf_pos:22272 ... ... [ 830.739031] Trigger:Stop
I can not do rmmod for ALSA driver. If I do sudo rmmod mydriver then it says "rmmod: ERROR: Module mydriver is in use"
How can I remove mydriver module from linux kernel ?
Likely some program is using the sound device. For example, a mixer applet or PulseAudio keeps opening the control device. Check it via "fuser -v /dev/snd/*"
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
Dear Takashi,
I would like you to review my driver, kindly tell me whether is it possible to review it. If yes, can you please share me git link where I can upload my driver for review .
Regards, Chakravarthi On Tue, Aug 7, 2018 at 5:41 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 14:08:05 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
In previous mail you have mentioned
So, either the measurement is wrong, or the stream is already screwed up at the time you call snd_pcm_period_elapsed().
what it means "measurement is wrong" and how to make that measurement is correct ?
See what I wrote: "either". I can't exclude the possibility that you are measuring the code calls incorrectly, of course. This is one case. Another case would be the incorrect state that is already screwed up at the time of snd_pcm_period_elapsed() call.
Takashi
Regards, Chakravarthi On Tue, Aug 7, 2018 at 5:33 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 13:59:46 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Trigger stop is getting called , because of this hwptr is zero and pointer call back is not getting called. Below is my log from driver.
[ 838.491681] Trigger:Start [ 839.522233] hwptr=0 buf_pos:3456 [ 839.522244] buf_pos :3456 bytes_to_frames:864 uhdc_audio_pcm_pointer_253 [ 839.522249] Trigger:Stop
Then you need to figure out the code path of the trigger stop.
In normal scenario, Trigger stop is not getting called and audio was able to render in the VLC application. Below log for normal scenario, [ 802.785893] Trigger:Start [ 814.288309] hwptr=0 buf_pos:6272 [ 814.288323] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288362] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288378] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.305079] hwptr=6272 buf_pos:9472 [ 814.305091] buf_pos :9472 bytes_to_frames:2368 uhdc_audio_pcm_pointer_253 [ 814.321741] hwptr=9472 buf_pos:12672 [ 814.321748] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321777] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321785] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.338452] hwptr=12672 buf_pos:15872 [ 814.338459] buf_pos :15872 bytes_to_frames:3968 uhdc_audio_pcm_pointer_253 [ 814.355242] hwptr=15872 buf_pos:19072 [ 814.355248] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355288] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355294] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.371822] hwptr=19072 buf_pos:22272 ... ... [ 830.739031] Trigger:Stop
I can not do rmmod for ALSA driver. If I do sudo rmmod mydriver then it says "rmmod: ERROR: Module mydriver is in use"
How can I remove mydriver module from linux kernel ?
Likely some program is using the sound device. For example, a mixer applet or PulseAudio keeps opening the control device. Check it via "fuser -v /dev/snd/*"
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
On Tue, 07 Aug 2018 14:14:35 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
I would like you to review my driver, kindly tell me whether is it possible to review it. If yes, can you please share me git link where I can upload my driver for review .
Chakravarthi, this is no "review" but an action called "debug". I can't waste my time for that, and you need to figure out the issue in your side.
Track the code and the PCM stream state. There are no many places that call the stop. Use the source, Luke.
Takashi
Regards, Chakravarthi On Tue, Aug 7, 2018 at 5:41 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 14:08:05 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
In previous mail you have mentioned
So, either the measurement is wrong, or the stream is already screwed up at the time you call snd_pcm_period_elapsed().
what it means "measurement is wrong" and how to make that measurement is correct ?
See what I wrote: "either". I can't exclude the possibility that you are measuring the code calls incorrectly, of course. This is one case. Another case would be the incorrect state that is already screwed up at the time of snd_pcm_period_elapsed() call.
Takashi
Regards, Chakravarthi On Tue, Aug 7, 2018 at 5:33 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 13:59:46 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Trigger stop is getting called , because of this hwptr is zero and pointer call back is not getting called. Below is my log from driver.
[ 838.491681] Trigger:Start [ 839.522233] hwptr=0 buf_pos:3456 [ 839.522244] buf_pos :3456 bytes_to_frames:864 uhdc_audio_pcm_pointer_253 [ 839.522249] Trigger:Stop
Then you need to figure out the code path of the trigger stop.
In normal scenario, Trigger stop is not getting called and audio was able to render in the VLC application. Below log for normal scenario, [ 802.785893] Trigger:Start [ 814.288309] hwptr=0 buf_pos:6272 [ 814.288323] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288362] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288378] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.305079] hwptr=6272 buf_pos:9472 [ 814.305091] buf_pos :9472 bytes_to_frames:2368 uhdc_audio_pcm_pointer_253 [ 814.321741] hwptr=9472 buf_pos:12672 [ 814.321748] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321777] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321785] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.338452] hwptr=12672 buf_pos:15872 [ 814.338459] buf_pos :15872 bytes_to_frames:3968 uhdc_audio_pcm_pointer_253 [ 814.355242] hwptr=15872 buf_pos:19072 [ 814.355248] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355288] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355294] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.371822] hwptr=19072 buf_pos:22272 ... ... [ 830.739031] Trigger:Stop
I can not do rmmod for ALSA driver. If I do sudo rmmod mydriver then it says "rmmod: ERROR: Module mydriver is in use"
How can I remove mydriver module from linux kernel ?
Likely some program is using the sound device. For example, a mixer applet or PulseAudio keeps opening the control device. Check it via "fuser -v /dev/snd/*"
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
Dear Takashi,
Thanks for your reply.
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
Is it 256 frames or 256 bytes ?
fuser -v /dev/snd/* output is USER PID ACCESS COMMAND /dev/snd/controlC0 Dell 1815 F..... pulseaudio
Regards, Chakravarthi On Tue, Aug 7, 2018 at 5:48 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 14:14:35 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
I would like you to review my driver, kindly tell me whether is it possible to review it. If yes, can you please share me git link where I can upload my driver for review .
Chakravarthi, this is no "review" but an action called "debug". I can't waste my time for that, and you need to figure out the issue in your side.
Track the code and the PCM stream state. There are no many places that call the stop. Use the source, Luke.
Takashi
Regards, Chakravarthi On Tue, Aug 7, 2018 at 5:41 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 14:08:05 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
In previous mail you have mentioned
So, either the measurement is wrong, or the stream is already screwed up at the time you call snd_pcm_period_elapsed().
what it means "measurement is wrong" and how to make that measurement is correct ?
See what I wrote: "either". I can't exclude the possibility that you are measuring the code calls incorrectly, of course. This is one case. Another case would be the incorrect state that is already screwed up at the time of snd_pcm_period_elapsed() call.
Takashi
Regards, Chakravarthi On Tue, Aug 7, 2018 at 5:33 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 13:59:46 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Trigger stop is getting called , because of this hwptr is zero and pointer call back is not getting called. Below is my log from driver.
[ 838.491681] Trigger:Start [ 839.522233] hwptr=0 buf_pos:3456 [ 839.522244] buf_pos :3456 bytes_to_frames:864 uhdc_audio_pcm_pointer_253 [ 839.522249] Trigger:Stop
Then you need to figure out the code path of the trigger stop.
In normal scenario, Trigger stop is not getting called and audio was able to render in the VLC application. Below log for normal scenario, [ 802.785893] Trigger:Start [ 814.288309] hwptr=0 buf_pos:6272 [ 814.288323] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288362] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.288378] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253 [ 814.305079] hwptr=6272 buf_pos:9472 [ 814.305091] buf_pos :9472 bytes_to_frames:2368 uhdc_audio_pcm_pointer_253 [ 814.321741] hwptr=9472 buf_pos:12672 [ 814.321748] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321777] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.321785] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253 [ 814.338452] hwptr=12672 buf_pos:15872 [ 814.338459] buf_pos :15872 bytes_to_frames:3968 uhdc_audio_pcm_pointer_253 [ 814.355242] hwptr=15872 buf_pos:19072 [ 814.355248] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355288] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.355294] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253 [ 814.371822] hwptr=19072 buf_pos:22272 ... ... [ 830.739031] Trigger:Stop
I can not do rmmod for ALSA driver. If I do sudo rmmod mydriver then it says "rmmod: ERROR: Module mydriver is in use"
How can I remove mydriver module from linux kernel ?
Likely some program is using the sound device. For example, a mixer applet or PulseAudio keeps opening the control device. Check it via "fuser -v /dev/snd/*"
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
On Tue, 07 Aug 2018 15:12:08 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Thanks for your reply.
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
Is it 256 frames or 256 bytes ?
In the case above it's in frames. But it can be defined in bytes depending on the hardware spec. Some hardware defines in the time unit (like msec), too.
fuser -v /dev/snd/* output is USER PID ACCESS COMMAND /dev/snd/controlC0 Dell 1815 F..... pulseaudio
Now you know it. And remember that PA is often die-hard.
Takashi
In the case above it's in frames. But it can be defined in bytes depending on the hardware spec. Some hardware defines in the time unit (like msec), too.
Can you please tell me how to define in bytes ?
Now you know it. And remember that PA is often die-hard.
So it means that I can not do rmmod until pulseaudio is removed , is it correct ?
Regards, Chakravarthi On Tue, Aug 7, 2018 at 6:45 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 15:12:08 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Thanks for your reply.
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
Is it 256 frames or 256 bytes ?
In the case above it's in frames. But it can be defined in bytes depending on the hardware spec. Some hardware defines in the time unit (like msec), too.
fuser -v /dev/snd/* output is USER PID ACCESS COMMAND /dev/snd/controlC0 Dell 1815 F..... pulseaudio
Now you know it. And remember that PA is often die-hard.
Takashi
On Tue, 07 Aug 2018 15:36:22 +0200, Chakravarthi Pradeep wrote:
In the case above it's in frames. But it can be defined in bytes depending on the hardware spec. Some hardware defines in the time unit (like msec), too.
Can you please tell me how to define in bytes ?
Read the source before asking like this. If not found, read the source again. If still it's not fulfilled, ask more specific questions.
The driver doesn't define it. Rather the driver lets ALSA PCM core choose the parameters given from user-space. But some parameters might not fit with the requirement of your hardware. For satisfying it, the driver may give hw constraints to PCM core beforehand, typically set in the open callback.
Now you know it. And remember that PA is often die-hard.
So it means that I can not do rmmod until pulseaudio is removed , is it correct ?
Yes. You cannot rmmod during any program is accessing to the sound device, not only PA.
Takashi
Regards, Chakravarthi On Tue, Aug 7, 2018 at 6:45 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 15:12:08 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Thanks for your reply.
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
Is it 256 frames or 256 bytes ?
In the case above it's in frames. But it can be defined in bytes depending on the hardware spec. Some hardware defines in the time unit (like msec), too.
fuser -v /dev/snd/* output is USER PID ACCESS COMMAND /dev/snd/controlC0 Dell 1815 F..... pulseaudio
Now you know it. And remember that PA is often die-hard.
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
Hi Takashi,
How to enable log from ALSA lib core or ALSA core , so that I will come to know why trigger stop call back is getting called back by itself.
ring bufffer size is 57600 and minimum bytes device generates per period is 3200(bytes). I have read one frame is 4 bytes from below link. https://www.alsa-project.org/main/index.php/FramesPeriods So is it correct to give below values to snd_pcm_hardware .period_bytes_min = 3200 /* per interrupt device provides minimum 3200 bytes of data*/ .periods_min = 72 /* 3200/4 /* 4 is because of (2 (channel )* (16 bits/2)) */
Regards, Chakravarthi On Tue, Aug 7, 2018 at 7:13 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 15:36:22 +0200, Chakravarthi Pradeep wrote:
In the case above it's in frames. But it can be defined in bytes depending on the hardware spec. Some hardware defines in the time unit (like msec), too.
Can you please tell me how to define in bytes ?
Read the source before asking like this. If not found, read the source again. If still it's not fulfilled, ask more specific questions.
The driver doesn't define it. Rather the driver lets ALSA PCM core choose the parameters given from user-space. But some parameters might not fit with the requirement of your hardware. For satisfying it, the driver may give hw constraints to PCM core beforehand, typically set in the open callback.
Now you know it. And remember that PA is often die-hard.
So it means that I can not do rmmod until pulseaudio is removed , is it correct ?
Yes. You cannot rmmod during any program is accessing to the sound device, not only PA.
Takashi
Regards, Chakravarthi On Tue, Aug 7, 2018 at 6:45 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 15:12:08 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Thanks for your reply.
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
Is it 256 frames or 256 bytes ?
In the case above it's in frames. But it can be defined in bytes depending on the hardware spec. Some hardware defines in the time unit (like msec), too.
fuser -v /dev/snd/* output is USER PID ACCESS COMMAND /dev/snd/controlC0 Dell 1815 F..... pulseaudio
Now you know it. And remember that PA is often die-hard.
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
On Thu, 09 Aug 2018 13:19:53 +0200, Chakravarthi Pradeep wrote:
Hi Takashi,
How to enable log from ALSA lib core or ALSA core , so that I will come to know why trigger stop call back is getting called back by itself.
Do printk, tracing, whatever you can see. We have the standard tracepoints, too, but maybe it's not what you need.
ring bufffer size is 57600 and minimum bytes device generates per period is 3200(bytes). I have read one frame is 4 bytes from below link. https://www.alsa-project.org/main/index.php/FramesPeriods So is it correct to give below values to snd_pcm_hardware .period_bytes_min = 3200 /* per interrupt device provides minimum 3200 bytes of data*/ .periods_min = 72 /* 3200/4 /* 4 is because of (2 (channel )* (16 bits/2)) */
period_bytes_min is 3200 bytes, so it looks correct. But periods_min is the minimal number of periods in a ring buffer. It can be calculated as (min buffer size) / (max period size).
Takashi
Regards, Chakravarthi On Tue, Aug 7, 2018 at 7:13 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 15:36:22 +0200, Chakravarthi Pradeep wrote:
In the case above it's in frames. But it can be defined in bytes depending on the hardware spec. Some hardware defines in the time unit (like msec), too.
Can you please tell me how to define in bytes ?
Read the source before asking like this. If not found, read the source again. If still it's not fulfilled, ask more specific questions.
The driver doesn't define it. Rather the driver lets ALSA PCM core choose the parameters given from user-space. But some parameters might not fit with the requirement of your hardware. For satisfying it, the driver may give hw constraints to PCM core beforehand, typically set in the open callback.
Now you know it. And remember that PA is often die-hard.
So it means that I can not do rmmod until pulseaudio is removed , is it correct ?
Yes. You cannot rmmod during any program is accessing to the sound device, not only PA.
Takashi
Regards, Chakravarthi On Tue, Aug 7, 2018 at 6:45 PM Takashi Iwai tiwai@suse.de wrote:
On Tue, 07 Aug 2018 15:12:08 +0200, Chakravarthi Pradeep wrote:
Dear Takashi,
Thanks for your reply.
The "period" in ALSA PCM definition represents the interval time (or frames) of the periodical interrupts on the ring buffer. If the irq is issued for each 256 frames while the ring buffer size is 1024 frames, periods = 1024/256 = 4. The periods_min defines the minimal number of periods the hardware may accept.
Is it 256 frames or 256 bytes ?
In the case above it's in frames. But it can be defined in bytes depending on the hardware spec. Some hardware defines in the time unit (like msec), too.
fuser -v /dev/snd/* output is USER PID ACCESS COMMAND /dev/snd/controlC0 Dell 1815 F..... pulseaudio
Now you know it. And remember that PA is often die-hard.
Takashi
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900
-- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900 _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
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Takashi Iwai