On Fri, 24 Jul 2015 09:52:14 +0200, Martin Geier wrote:
Thanks for help,
in attachment is patch with suggest change. Is the patch acceptable?
I prefer a bit clearer name like params_saved or such, but yes, it's what I had in my mind, too. Could you tidy it up and resubmit with the more description -- why it's needed and what does it? Last but not least, it'd be helpful if you give also signed-off-by tag.
thanks,
Takashi
Martin
On 23.07.2015 10:11, Takashi Iwai wrote:
On Tue, 21 Jul 2015 10:52:01 +0200, Martin Geier wrote:
Hallo,
I tried to configure alsa device with snd_pcm_set_params function, requested parameters was: channel 2, rate: 22050, soft_resample: 1, latency: 50000
Function snd_pcm_hw_params_set_buffer_time_near and snd_pcm_hw_param_set_near is called with: min: 50000, max: 50000, mindir: 0, maxdir: -1
and input params was:
ACCESS: RW_INTERLEAVED FORMAT: S16_LE SUBFORMAT: STD SAMPLE_BITS: 16 FRAME_BITS: 32 CHANNELS: 2 RATE: 22050 PERIOD_TIME: (362 743039) PERIOD_SIZE: [8 16384] PERIOD_BYTES: [32 65536] PERIODS: [2 19] BUFFER_TIME: (725 1486078) BUFFER_SIZE: [16 32768] BUFFER_BYTES: [64 131072] TICK_TIME: ALL
unfortunately, this function fails, on function snd_pcm_hw_param_set_first:
ALSA ERROR hw_params: set_near (BUFFER_TIME) value = 50000 : Invalid argument ACCESS: RW_INTERLEAVED FORMAT: S16_LE SUBFORMAT: STD SAMPLE_BITS: 16 FRAME_BITS: 32 CHANNELS: 2 RATE: 22050 PERIOD_TIME: (4580 5533) PERIOD_SIZE: NONE PERIOD_BYTES: [404 488] PERIODS: 10 BUFFER_TIME: (50022 50023) BUFFER_SIZE: 1103 BUFFER_BYTES: 4412 TICK_TIME: ALL
This shouldn't be problem because in snd_pcm_set_params is snd_pcm_hw_params_set_period_time_near called. This function should be called with same params as snd_pcm_hw_params_set_buffer_time_near but the input params are:
snd_pcm_hw_param_set_near: min: 12500, max: 12500, mindir: 0, maxdir: -1 hw_params: snd_pcm_hw_param_set_near (PERIOD_TIME) ACCESS: RW_INTERLEAVED FORMAT: S16_LE SUBFORMAT: STD SAMPLE_BITS: 16 FRAME_BITS: 32 CHANNELS: 2 RATE: 22050 PERIOD_TIME: (4580 5533) PERIOD_SIZE: NONE PERIOD_BYTES: [404 488] PERIODS: 10 BUFFER_TIME: (50022 50023) BUFFER_SIZE: 1103 BUFFER_BYTES: 4412 TICK_TIME: ALL
because in snd_pcm_hw_param_set_near is
if (last) err = snd_pcm_hw_param_set_last(pcm, params, var, val, dir); else err = snd_pcm_hw_param_set_first(pcm, params, var, val, dir); if (err < 0) dump_hw_params(params, "set_near", var, *val, err); return err;
and in error part is only debug output and not restore original parameters.
Environment: alsa-lib 1.0.27.1 TI AM335x soc
Simple fix is attached, but I am not sure if it is correct.
Thanks for analysis and patch. It's however rather a bug in snd_pcm_set_params(). There is no guarantee to keep the old value in snd_pcm_set_*(), thus the caller needs to take care of it instead.
Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
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From 2d4e94d974678bbd4826b33c59c275d1f34edc20 Mon Sep 17 00:00:00 2001
From: Martin Geier martin.geier@streamunlimited.com Date: Fri, 24 Jul 2015 09:30:57 +0200 Subject: [PATCH] restore hw params on set rate failed
pcm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c index ca4d416..b6de73e 100644 --- a/src/pcm/pcm.c +++ b/src/pcm/pcm.c @@ -7883,7 +7883,7 @@ int snd_pcm_set_params(snd_pcm_t *pcm, int soft_resample, unsigned int latency) {
snd_pcm_hw_params_t *params;
snd_pcm_hw_params_t *params, pparams; snd_pcm_sw_params_t *swparams; const char *s = snd_pcm_stream_name(snd_pcm_stream(pcm)); snd_pcm_uframes_t buffer_size, period_size;@@ -7936,9 +7936,11 @@ int snd_pcm_set_params(snd_pcm_t *pcm, return -EINVAL; } /* set the buffer time */
- pparams = *params; err = INTERNAL(snd_pcm_hw_params_set_buffer_time_near)(pcm, params, &latency, NULL); if (err < 0) { /* error path -> set period size as first */
*params = pparams; /* set the period time */ period_time = latency / 4; err = INTERNAL(snd_pcm_hw_params_set_period_time_near)(pcm, params, &period_time, NULL);-- 1.9.1