On Thu, 20 Jun 2024 04:40:18 +0200,
Shengjiu Wang wrote:
>
> When dmaengine supports pause function, in suspend state,
> dmaengine_pause() is called instead of dmaengine_terminate_async(),
>
> In end of playback stream, the runtime->state will go to
> SNDRV_PCM_STATE_DRAINING, if system suspend & resume happen
> at this time, application will not resume playback stream, the
> stream will be closed directly, the dmaengine_terminate_async()
> will not be called before the dmaengine_synchronize(), which
> violates the call sequence for dmaengine_synchronize().
Hmm, I can't follow this state change.
Do you mean that:
- snd_pcm_drain() is performed for a playback stream
- while draining operation, the system goes to suspend
- the system resumes (but the application doesn't call resume yet)
- The stream is closed (without calling resume)
??
If so, it's rather an inconsistent PCM state in the core side, and can
be fixed by a simple call like below:
-- 8< --
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -2700,6 +2700,7 @@ void snd_pcm_release_substream(struct snd_pcm_substream *substream)
if (substream->ref_count > 0)
return;
+ snd_pcm_resume(substream);
snd_pcm_drop(substream);
if (substream->hw_opened) {
if (substream->runtime->state != SNDRV_PCM_STATE_OPEN)
-- 8< --
This will be no-op for the PCM device without SNDRV_PCM_INFO_RESUME.
But, this may need more rework, too; admittedly it imposes the
unnecessary resume of the stream although it shall be stopped and
closed immediately after that. We may have some optimization in
addition.
thanks,
Takashi
