[pulseaudio-discuss] [alsa-devel] Adjust volume may cause audio playback corruption

[Takashi Iwai]

At Tue, 15 May 2012 16:30:14 +0800,
cee1 wrote:
> 
> Witch a patch[1] of PA which dumps playback PCM data, I found the
> dumped data(with ./wavformat.py[2] <dumpped_data> to convert to wav
> file) is not corrupted.
> Since PA uses mmap to transfer PCM data, the driver's DMA buffer
> should also be "good".
> 
> It seems related to HDA controller of SB710, I tried HDMI output, and
> can reproduce the problem
> too(http://dev.lemote.com/files/upload/software/PA-apc/HDMI-corrupted_sound.ogg).

If you are using the recent kernel, try snoop=off option of
snd-hda-intel driver.  The recent AMD and VIA controllers are known to
work with the non-snooping mode.


Takashi

> 2012/5/12 cee1 <fykcee1 at gmail.com>:
> > Hi all,
> >
> > We're using PA on our product, and sometimes audio playback may
> > corrupt after adjusting volume.
> >
> > We found a way to (relatively) easily reproduce the problem:
> > 1. Play sample.mp3 through totem in repeat mode.
> > 2. In gnome-volume-control, Hardware tap, repeat to shift between "Off
> > profile" and "Analog Stereo Duplex profile".
> >
> > When the problem happens, the corruption continues until I:
> > * Do one more shift between "Off profile" and "Analog Stereo Duplex profile".
> > * Close totem (close all PA playback clients).
> > * Adjust volume.
> >
> > When the problem happens, open another PA client doing audio playback,
> > is also corrupt.
> >
> > Some additional information:
> > * Output of alsa-info.sh on our product:
> > http://dev.lemote.com/files/upload/software/PA-apc/alsa-info-lemote
> > * PA daemon log:
> > http://dev.lemote.com/files/upload/software/PA-apc/pulseaudio.log
> > * The corrupted sound:
> > http://dev.lemote.com/files/upload/software/PA-apc/corrupted_sound.ogg
> > * The sample mp3: http://dev.lemote.com/files/upload/software/PA-apc/sample.mp3
> >
> > We've tried PA 1.0-0ubuntu3, 1.1-0ubuntu15 and 2.0, the problem continues.
> >
> > The problem can also be reproduced on an AMD turion 64 x2 board with
> > ubuntu 10.10 and ubuntu 12.04:
> > * Output of alsa-info:
> >  ubuntu 10.10(32bit)
> > http://dev.lemote.com/files/upload/software/PA-apc/alsa-info-ubuntu-10.10
> >  ubuntu 12.04(32bit)
> > http://dev.lemote.com/files/upload/software/PA-apc/alsa-info-ubuntu-12.04
> >
> > Note:
> > * The AMD turion 64 x2 board uses the same chipset as our product.
> > * gnome-volume-control is removed in ubuntu 12.04, thus we compiled
> > it: http://dev.lemote.com/files/upload/software/PA-apc/gnome-volume-control
> 
> ----
> [1] http://dev.lemote.com/files/upload/software/PA-apc/debug/debug-alsa-sink.patch
> [2] http://dev.lemote.com/files/upload/software/PA-apc/debug/wavformat.py
> 
> 
> 
> -- 
> Regards,
> 
> - cee1
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