[alsa-devel] [PATCH] Tell user that stream to be rewound is suspended
Return STRPIPE instead of EBADF when userspace attempts to rewind of forward a stream that was suspended in meanwhile, so that it can be recovered by snd_pcm_recover().
This was causing Pulseaudio to unload the ALSA sink module under a race condition when it attempted to rewind the stream right after resume from suspend, before writing to the stream which would cause it to revive the stream otherwise. Tested to work with Pulseaudio patched to attempt to snd_pcm_recover() upon receiving an error from snd_pcm_rewind().
Signed-off-by: Lubomir Rintel lkundrak@v3.sk --- sound/core/pcm_native.c | 12 ++++++++++++ 1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index ac2150e..d89c816 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -2208,6 +2208,9 @@ static snd_pcm_sframes_t snd_pcm_playback_rewind(struct snd_pcm_substream *subst case SNDRV_PCM_STATE_XRUN: ret = -EPIPE; goto __end; + case SNDRV_PCM_STATE_SUSPENDED: + ret = -ESTRPIPE; + goto __end; default: ret = -EBADFD; goto __end; @@ -2253,6 +2256,9 @@ static snd_pcm_sframes_t snd_pcm_capture_rewind(struct snd_pcm_substream *substr case SNDRV_PCM_STATE_XRUN: ret = -EPIPE; goto __end; + case SNDRV_PCM_STATE_SUSPENDED: + ret = -ESTRPIPE; + goto __end; default: ret = -EBADFD; goto __end; @@ -2299,6 +2305,9 @@ static snd_pcm_sframes_t snd_pcm_playback_forward(struct snd_pcm_substream *subs case SNDRV_PCM_STATE_XRUN: ret = -EPIPE; goto __end; + case SNDRV_PCM_STATE_SUSPENDED: + ret = -ESTRPIPE; + goto __end; default: ret = -EBADFD; goto __end; @@ -2345,6 +2354,9 @@ static snd_pcm_sframes_t snd_pcm_capture_forward(struct snd_pcm_substream *subst case SNDRV_PCM_STATE_XRUN: ret = -EPIPE; goto __end; + case SNDRV_PCM_STATE_SUSPENDED: + ret = -ESTRPIPE; + goto __end; default: ret = -EBADFD; goto __end;
On Sun, 2009-08-02 at 18:14 +0200, Lubomir Rintel wrote:
Return STRPIPE instead of EBADF when userspace attempts to rewind of forward a stream that was suspended in meanwhile, so that it can be recovered by snd_pcm_recover().
This was causing Pulseaudio to unload the ALSA sink module under a race condition when it attempted to rewind the stream right after resume from suspend, before writing to the stream which would cause it to revive the stream otherwise. Tested to work with Pulseaudio patched to attempt to snd_pcm_recover() upon receiving an error from snd_pcm_rewind().
The userspace part is filed here: http://www.pulseaudio.org/ticket/616
At Sun, 2 Aug 2009 18:14:44 +0200, Lubomir Rintel wrote:
Return STRPIPE instead of EBADF when userspace attempts to rewind of forward a stream that was suspended in meanwhile, so that it can be recovered by snd_pcm_recover().
This was causing Pulseaudio to unload the ALSA sink module under a race condition when it attempted to rewind the stream right after resume from suspend, before writing to the stream which would cause it to revive the stream otherwise. Tested to work with Pulseaudio patched to attempt to snd_pcm_recover() upon receiving an error from snd_pcm_rewind().
Signed-off-by: Lubomir Rintel lkundrak@v3.sk
The change looks fine, but I think this isn't for stable kernel since this is actually an ABI extension.
For testing, I'm going to apply this to sound-unstable tree for the time being. I'll merge to the main sound tree soon later, though.
thanks,
Takashi
sound/core/pcm_native.c | 12 ++++++++++++ 1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index ac2150e..d89c816 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -2208,6 +2208,9 @@ static snd_pcm_sframes_t snd_pcm_playback_rewind(struct snd_pcm_substream *subst case SNDRV_PCM_STATE_XRUN: ret = -EPIPE; goto __end;
- case SNDRV_PCM_STATE_SUSPENDED:
ret = -ESTRPIPE;goto __end;@@ -2253,6 +2256,9 @@ static snd_pcm_sframes_t snd_pcm_capture_rewind(struct snd_pcm_substream *substr case SNDRV_PCM_STATE_XRUN: ret = -EPIPE; goto __end;
- case SNDRV_PCM_STATE_SUSPENDED:
ret = -ESTRPIPE;goto __end;@@ -2299,6 +2305,9 @@ static snd_pcm_sframes_t snd_pcm_playback_forward(struct snd_pcm_substream *subs case SNDRV_PCM_STATE_XRUN: ret = -EPIPE; goto __end;
- case SNDRV_PCM_STATE_SUSPENDED:
ret = -ESTRPIPE;goto __end;@@ -2345,6 +2354,9 @@ static snd_pcm_sframes_t snd_pcm_capture_forward(struct snd_pcm_substream *subst case SNDRV_PCM_STATE_XRUN: ret = -EPIPE; goto __end;
- case SNDRV_PCM_STATE_SUSPENDED:
ret = -ESTRPIPE;goto __end;-- 1.6.2.5
participants (2)
-
Lubomir Rintel -
Takashi Iwai