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| author | Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2021-06-10 12:17:31 +0900 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2021-06-10 09:49:54 +0200 |
| commit | 47271b1b98c980e915c0332eb5e8b2f273b2cd78 (patch) | |
| tree | 6900897ad9032de6a41fa5e996c01901a1447523 /include | |
| parent | 6ea9a2b84cc354ffd028195edb4e3d60d47f7bcb (diff) | |
| download | linux-47271b1b98c980e915c0332eb5e8b2f273b2cd78.tar.bz2 | |
ALSA: pcm: add snd_pcm_period_elapsed() variant without acquiring lock of PCM substream
Current implementation of ALSA PCM core has a kernel API,
snd_pcm_period_elapsed(), for drivers to queue event to awaken processes
from waiting for available frames. The function voluntarily acquires lock
of PCM substream, therefore it is not called in process context for any
PCM operation since the lock is already acquired.
It is convenient for packet-oriented driver, at least for drivers to audio
and music unit in IEEE 1394 bus. The drivers are allowed by Linux
FireWire subsystem to process isochronous packets queued till recent
isochronous cycle in process context in any time.
This commit adds snd_pcm_period_elapsed() variant,
snd_pcm_period_elapsed_without_lock(), for drivers to queue the event in
the process context.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210610031733.56297-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'include')
| -rw-r--r-- | include/sound/pcm.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/sound/pcm.h b/include/sound/pcm.h index 2e1200d17d0c..bae90696cd06 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -1066,6 +1066,7 @@ void snd_pcm_set_ops(struct snd_pcm * pcm, int direction, void snd_pcm_set_sync(struct snd_pcm_substream *substream); int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream, unsigned int cmd, void *arg); +void snd_pcm_period_elapsed_under_stream_lock(struct snd_pcm_substream *substream); void snd_pcm_period_elapsed(struct snd_pcm_substream *substream); snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream, void *buf, bool interleaved, |