[alsa-devel] Understanding SND_PCM_INFO_ [BATCH, BLOCK_TRANSFER, DOUBLE]

[Eliot Blennerhassett]

I've been looking at these info flags, and whether they cause the driver
to be accessed any differently by the upper layers.
So far I can find hardly any examples where they are used in any
significant way - what am I missing if anything?

SND_/SNDRV_
_PCM_INFO_BATCH
double buffering
skips the check enabled by XRUN_DEBUG_JIFFIESCHECK
alsa-lib returns it in snd_pcm_hw_params_is_batch()

_PCM_INFO_BLOCK_TRANSFER
/* hardware transfer block of samples */
translated by pcm_oss.c into ~DSP_CAP_REALTIME
lib: snd_pcm_hw_params_is_block_transfer()

_PCM_INFO_DOUBLE
/* double buffering needed for PCM start/stop */
snd_pcm_hw_params_is_double()

I don't see any of these functions called by aplay...


--
Eliot