[alsa-devel] buffer_size return by snd_pcm_hw_params_get_buffer_size_max
it seem that the value return by snd_pcm_hw_params_get_buffer_size_max() depend on /proc/asound/Intel/pcm0p/sub0/prealloc
Is it a bug in alsa-lib or snd-hda-intel driver
refer to pulseaudio/src/modules/alsa/alsa-util.c
if ((ret = snd_pcm_hw_params_get_buffer_size_max(hwparams, &max_frames)) < 0) pa_log_warn("snd_pcm_hw_params_get_buffer_size_max() failed: %s", pa_alsa_strerror(ret)); else pa_log_debug("Maximum hw buffer size is %lu ms", (long unsigned) (max_frames * PA_MSEC_PER_SEC / _ss.rate));
cat /proc/asound/Intel/pcm0p/sub0/prealloc 64
D: alsa-util.c: Checking for superset analog-stereo (front:%f) D: alsa-util.c: Trying front:1 with SND_PCM_NO_AUTO_FORMAT ... D: alsa-util.c: Managed to open front:1 I: alsa-util.c: Trying to disable ALSA period wakeups, using timers only D: alsa-util.c: Maximum hw buffer size is 371 ms D: alsa-util.c: Set buffer size first (to 88200 samples), period size second (to 88200 samples). I: alsa-util.c: ALSA period wakeups disabled I: alsa-source.c: Successfully opened device front:1. I: alsa-source.c: Selected mapping 'Analog Stereo' (analog-stereo). I: alsa-source.c: Successfully enabled mmap() mode. I: alsa-source.c: Successfully enabled timer-based scheduling mode.
echo 32768 > /proc/asound/Intel/pcm0p/sub0/prealloc
D: alsa-util.c: Checking for superset analog-stereo (front:%f) D: alsa-util.c: Trying front:1 with SND_PCM_NO_AUTO_FORMAT ... D: alsa-util.c: Managed to open front:1 I: alsa-util.c: Trying to disable ALSA period wakeups, using timers only D: alsa-util.c: Maximum hw buffer size is 190217 ms D: alsa-util.c: Set buffer size first (to 88200 samples), period size second (to 88200 samples). I: alsa-util.c: ALSA period wakeups disabled I: alsa-sink.c: Successfully opened device front:1. I: alsa-sink.c: Selected mapping 'Analog Stereo' (analog-stereo). I: alsa-sink.c: Successfully enabled mmap() mode. I: alsa-sink.c: Successfully enabled timer-based scheduling mode.
At Mon, 4 Apr 2011 11:54:45 +0800, Raymond Yau wrote:
it seem that the value return by snd_pcm_hw_params_get_buffer_size_max() depend on /proc/asound/Intel/pcm0p/sub0/prealloc
Is it a bug in alsa-lib or snd-hda-intel driver
No bug. This is the designed behavior.
Takashi
2011/4/4 Takashi Iwai tiwai@suse.de
At Mon, 4 Apr 2011 11:54:45 +0800, Raymond Yau wrote:
it seem that the value return by snd_pcm_hw_params_get_buffer_size_max() depend on /proc/asound/Intel/pcm0p/sub0/prealloc
Is it a bug in alsa-lib or snd-hda-intel driver
No bug. This is the designed behavior.
Takashi
This explain why my hda-intel fail in tsched=0 but work quite well in tsched=1
I: module-suspend-on-idle.c: Sink alsa_output.1.analog-stereo idle for too long, suspending ... D: sink.c: Suspend cause of sink alsa_output.1.analog-stereo is 0x0004, suspending E: alsa-util.c: snd_pcm_dump(): E: alsa-util.c: Soft volume PCM E: alsa-util.c: Control: PCM Playback Volume E: alsa-util.c: min_dB: -51 E: alsa-util.c: max_dB: 0 E: alsa-util.c: resolution: 256 E: alsa-util.c: Its setup is: E: alsa-util.c: stream : PLAYBACK E: alsa-util.c: access : MMAP_INTERLEAVED E: alsa-util.c: format : S16_LE E: alsa-util.c: subformat : STD E: alsa-util.c: channels : 2 E: alsa-util.c: rate : 44100 E: alsa-util.c: exact rate : 44100 (44100/1) E: alsa-util.c: msbits : 16 E: alsa-util.c: buffer_size : 16384 E: alsa-util.c: period_size : 8192 E: alsa-util.c: period_time : 185759 E: alsa-util.c: tstamp_mode : ENABLE E: alsa-util.c: period_step : 1 E: alsa-util.c: avail_min : 8192 E: alsa-util.c: period_event : 1 E: alsa-util.c: start_threshold : -1 E: alsa-util.c: stop_threshold : 1073741824 E: alsa-util.c: silence_threshold: 0 E: alsa-util.c: silence_size : 0 E: alsa-util.c: boundary : 1073741824 E: alsa-util.c: Slave: Hardware PCM card 1 'HDA Intel' device 0 subdevice 0 E: alsa-util.c: Its setup is: E: alsa-util.c: stream : PLAYBACK E: alsa-util.c: access : MMAP_INTERLEAVED E: alsa-util.c: format : S16_LE E: alsa-util.c: subformat : STD E: alsa-util.c: channels : 2 E: alsa-util.c: rate : 44100 E: alsa-util.c: exact rate : 44100 (44100/1) E: alsa-util.c: msbits : 16 E: alsa-util.c: buffer_size : 16384 E: alsa-util.c: period_size : 8192 E: alsa-util.c: period_time : 185759 E: alsa-util.c: tstamp_mode : ENABLE E: alsa-util.c: period_step : 1 E: alsa-util.c: avail_min : 8192 E: alsa-util.c: period_event : 1 E: alsa-util.c: start_threshold : -1 E: alsa-util.c: stop_threshold : 1073741824 E: alsa-util.c: silence_threshold: 0 E: alsa-util.c: silence_size : 0 E: alsa-util.c: boundary : 1073741824 E: alsa-util.c: appl_ptr : 163888 E: alsa-util.c: hw_ptr : 227328 I: alsa-sink.c: Underrun! I: alsa-sink.c: Device suspended... I: module-suspend-on-idle.c: Sink alsa_output.0.analog-stereo idle for too long, suspending ... D: sink.c: Suspend cause of sink alsa_output.0.analog-stereo is 0x0004, suspending I: alsa-sink.c: Device suspended...
participants (2)
-
Raymond Yau -
Takashi Iwai