[alsa-devel] Bug#536896: linux-image-2.6.26-2-amd64: audio popping with gstreamer using apps when using amd64 kernel and i386 userspace

[Ben Hutchings]

On Mon, 2010-04-12 at 09:26 +0200, Takashi Iwai wrote:
> At Sun, 11 Apr 2010 21:25:16 +0100,
> Ben Hutchings wrote:
> > 
> > [1  <text/plain; UTF-8 (quoted-printable)>]
> > [Earlier messages can be found at http://bugs.debian.org/536896 ]
> > 
> > On Mon, 2010-04-12 at 01:08 +0800, James Andrewartha wrote:
[...]
> > > Author: Takashi Iwai <tiwai at suse.de>  2008-01-09 02:08:14
> > > Committer: Jaroslav Kysela <perex at perex.cz>  2008-02-01 01:29:47
> > > Parent: d948035a928400ae127c873fbf771389bee18949 ([ALSA] Remove PCM xfer_align sw params)
> > > 
> > >     [ALSA] PCM - clean up snd_pcm_lib_read/write
> > >     
> > >     Introduce a common helper function for snd_pcm_lib_read and snd_pcm_lib_write
> > >     for cleaning up the code.
> > >     
> > >     Signed-off-by: Takashi Iwai <tiwai at suse.de>
> > >     Signed-off-by: Jaroslav Kysela <perex at perex.cz>
> > > 
> > > I don't know anything about this code, but I'm happy to deal with upstream 
> > > if you'd prefer me to.
> > 
> > The above commit is supposed to be cleanup, but it has at least one
> > semantic change: snd_pcm_mmap_control::avail_min no longer applies to
> > non-blocking file handles.  I don't know whether this is was an
> > intentional or unintentional change, but it wasn't commented.  I also
> > don't know whether this can explain the popping, but I expect that it
> > has changed the timing of audio I/O.
> 
> The above change is essentially a fix of the buggy behavior for
> non-blocking access.  avail_min is the definition for wake-up
> behavior, and it doesn't define the blocking behavior.
> But, it's possible that this changes the timing, indeed.  If so, it
> implies that the app expects somehow wrongly.

Thanks for your quick response.  I will reassign this bug to the
applications that were mentioned.

Ben.

-- 
Ben Hutchings
Once a job is fouled up, anything done to improve it makes it worse.
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