From: Timo Wischer twischer@de.adit-jv.com
Some applications do not expect that get_period_size_min() could return 0. Therefore these applications cannot use the null plugin without this patch. Due to there is no use case for having a period size of 0 this patch disallows a period size of 0 when using the null plugin.
Signed-off-by: Timo Wischer twischer@de.adit-jv.com ---
Hi Takashi,
Why 32?
I thought there is also no use case for a period of 1 frame. Therefore I increased it to a 2^n value to also lower the CPU usage in case of null plugin.
Or does it cause a problem?
I do not see any issues here. But for example portaudio will automatically choose a period size of 1 frame which will result in a higher CPU load.
But anyway I would also be fine with this higher CPU load if you prefer this patch.
Best regards
Timo
src/pcm/pcm_null.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/src/pcm/pcm_null.c b/src/pcm/pcm_null.c index ff61624..1d81548 100644 --- a/src/pcm/pcm_null.c +++ b/src/pcm/pcm_null.c @@ -261,7 +261,17 @@ static snd_pcm_sframes_t snd_pcm_null_mmap_commit(snd_pcm_t *pcm,
static int snd_pcm_null_hw_refine(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params) { - int err = snd_pcm_hw_refine_soft(pcm, params); + int err; + + /* Do not return a period size of 0 because for example portaudio cannot + * handle it. + */ + err = _snd_pcm_hw_param_set_min(params, SND_PCM_HW_PARAM_PERIOD_SIZE, 1, + 0); + if (err < 0) + return err; + + err = snd_pcm_hw_refine_soft(pcm, params); params->info = SND_PCM_INFO_MMAP | SND_PCM_INFO_MMAP_VALID | SND_PCM_INFO_RESUME | SND_PCM_INFO_PAUSE; params->fifo_size = 0;