Re: Adjust volume may cause audio playback corruption

Re: Adjust volume may cause audio playback corruption

[cee1]

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).
2012/5/12 cee1 <fykcee1@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

Re: 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@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
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
> 
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Re: Adjust volume may cause audio playback corruption

[cee1]

Hi,

Thanks for reply.
2012/5/15 Takashi Iwai <tiwai@suse.de>
>
> 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.

I'm trying snd-hda-intel.snoop=0 under ubuntu10.10(32bit) with kernel
from ubuntu 12.04(32bit), I still can reproduce it.

BTW, what is difference between snoop and no snoop?
Enable no snoop mode will render no sound on our platform(which is
mips compatible).



----
Regards,
cee1

Re: Adjust volume may cause audio playback corruption

[Takashi Iwai]

At Thu, 17 May 2012 17:15:24 +0800,
cee1 wrote:
> 
> Hi,
> 
> Thanks for reply.
> 2012/5/15 Takashi Iwai <tiwai@suse.de>
> >
> > 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.
> 
> I'm trying snd-hda-intel.snoop=0 under ubuntu10.10(32bit) with kernel
> from ubuntu 12.04(32bit), I still can reproduce it.
> 
> BTW, what is difference between snoop and no snoop?
> Enable no snoop mode will render no sound on our platform(which is
> mips compatible).

Ah, *this* is the biggest missing information.
The non-snoop mode is implemented currently only for x86-64.

The non-snoop mode requires the non-cached pages and its mmap.
This implementation is pretty arch-dependency, and currently no
properl way is provided for MIPS.  On such platforms, mmap doesn't
work reliably, unfortunately.


Takashi
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Re: Adjust volume may cause audio playback corruption

[cee1]

2012/5/12 cee1 <fykcee1@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
When the problem happens today, I notice:
1) PA complains "alsa-source.c: Overrun!". I doesn't run any recording
 application then. Curious.
2) Playback becomes good automatically when play sample.mp3 again(note
totem is in repeat playing mode). It says sink becomes idle(I didn't
touch totem, so totem should keep playing back).

Any idea?

Following is PA daemon log:
I: [alsa-source] ratelimit.c: 1226 events suppressed
I: [alsa-source] alsa-source.c: Overrun!
I: [alsa-source] alsa-source.c: Increasing minimal latency to 1.00 ms
D: [alsa-source] alsa-source.c: latency set to 20.00ms
D: [alsa-source] alsa-source.c: hwbuf_unused=62008
D: [alsa-source] alsa-source.c: setting avail_min=442
I: [alsa-source] alsa-source.c: Overrun!
I: [alsa-source] alsa-source.c: Increasing minimal latency to 2.00 ms
D: [alsa-source] alsa-source.c: latency set to 20.00ms
D: [alsa-source] alsa-source.c: hwbuf_unused=62008
D: [alsa-source] alsa-source.c: setting avail_min=442
I: [alsa-source] alsa-source.c: Overrun!
I: [alsa-source] alsa-source.c: Increasing minimal latency to 4.00 ms
D: [alsa-source] alsa-source.c: latency set to 20.00ms
D: [alsa-source] alsa-source.c: hwbuf_unused=62008
D: [alsa-source] alsa-source.c: setting avail_min=442
I: [alsa-source] alsa-source.c: Overrun!
I: [alsa-source] alsa-source.c: Increasing minimal latency to 8.00 ms
D: [alsa-source] alsa-source.c: latency set to 20.00ms
D: [alsa-source] alsa-source.c: hwbuf_unused=62008
D: [alsa-source] alsa-source.c: setting avail_min=442
I: [alsa-source] alsa-source.c: Overrun!
I: [alsa-source] alsa-source.c: Increasing minimal latency to 16.00 ms
D: [alsa-source] alsa-source.c: latency set to 20.00ms
D: [alsa-source] alsa-source.c: hwbuf_unused=62008
D: [alsa-source] alsa-source.c: setting avail_min=442
I: [alsa-source] alsa-source.c: Overrun!
I: [alsa-source] alsa-source.c: Increasing minimal latency to 26.00 ms
D: [alsa-source] alsa-source.c: latency set to 26.00ms
D: [alsa-source] alsa-source.c: hwbuf_unused=60952
D: [alsa-source] alsa-source.c: setting avail_min=706
D: [alsa-sink] protocol-native.c: Underrun on 'Playback Stream', 0
bytes in queue.
D: [alsa-sink] protocol-native.c: Requesting rewind due to rewrite.
D: [alsa-sink] sink-input.c: Requesting rewind due to corking
D: [alsa-sink] alsa-sink.c: Requested to rewind 16208 bytes.
D: [alsa-sink] alsa-sink.c: Limited to 15096 bytes.
D: [alsa-sink] alsa-sink.c: before: 3774
D: [alsa-sink] alsa-sink.c: after: 3642
D: [alsa-sink] alsa-sink.c: Rewound 14568 bytes.
D: [alsa-sink] sink.c: Processing rewind...
D: [alsa-sink] sink.c: latency = 4156
D: [alsa-sink] sink-input.c: Have to rewind 14568 bytes on render memblockq.
D: [alsa-sink] sink-input.c: Have to rewind 29136 bytes on implementor.
D: [alsa-sink] source.c: Processing rewind...
D: [pulseaudio] module-suspend-on-idle.c: Sink
alsa_output.pci-0000_00_14.2.analog-stereo becomes idle, timeout in 5
seconds.
D: [alsa-sink] protocol-native.c: Requesting rewind due to end of underrun.
D: [alsa-sink] protocol-native.c: Requesting rewind due to end of underrun.
D: [alsa-sink] protocol-native.c: Requesting rewind due to end of underrun.
D: [alsa-sink] protocol-native.c: Requesting rewind due to end of underrun.
D: [alsa-sink] protocol-native.c: Requesting rewind due to end of underrun.
D: [pulseaudio] sink.c: Suspend cause of sink
alsa_output.pci-0000_00_14.2.analog-stereo is 0x0004, suspending
I: [alsa-sink] alsa-sink.c: Device suspended...
I: [pulseaudio] alsa-sink.c: Updating rate for device front:0, new rate is 44100
I: [pulseaudio] sink.c: Changed sampling rate successfully
D: [alsa-sink] protocol-native.c: Requesting rewind due to end of underrun.
D: [alsa-sink] sink-input.c: Requesting rewind due to uncorking
D: [pulseaudio] sink.c: Suspend cause of sink
alsa_output.pci-0000_00_14.2.analog-stereo is 0x0000, resuming
I: [alsa-sink] alsa-sink.c: Trying resume...
I: [alsa-sink] alsa-util.c: Trying to disable ALSA period wakeups,
using timers only
D: [alsa-sink] alsa-util.c: Maximum hw buffer size is 371 ms
D: [alsa-sink] alsa-util.c: Set buffer size first (to 16384 samples),
period size second (to 8192 samples).
I: [alsa-sink] alsa-util.c: ALSA period wakeups disabled
D: [alsa-sink] alsa-sink.c: Latency set to 90.00ms
D: [alsa-sink] alsa-sink.c: hwbuf_unused=49660
D: [alsa-sink] alsa-sink.c: setting avail_min=15503
I: [alsa-sink] alsa-sink.c: Time scheduling watermark is 20.00ms
I: [alsa-sink] alsa-sink.c: Resumed successfully...
D: [pulseaudio] core-subscribe.c: Dropped redundant event due to change event.
I: [alsa-sink] alsa-sink.c: Starting playback.
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.
D: [pulseaudio] core-subscribe.c: Dropped redundant event due to change event.
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.
D: [pulseaudio] module-suspend-on-idle.c: Sink
alsa_output.pci-0000_00_14.2.analog-stereo becomes busy.
D: [pulseaudio] module-udev-detect.c: /dev/snd/controlC0 is accessible: yes
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.
D: [alsa-sink] alsa-sink.c: Cutting sleep time for the initial
iterations by half.


>
> 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



-- 
Regards,

- cee1

Re: Adjust volume may cause audio playback corruption

[cee1]

2012/5/17 cee1 <fykcee1@gmail.com>:
> 2012/5/12 cee1 <fykcee1@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
> When the problem happens today, I notice:
> 1) PA complains "alsa-source.c: Overrun!". I doesn't run any recording
>  application then. Curious.
> 2) Playback becomes good automatically when play sample.mp3 again(note
> totem is in repeat playing mode). It says sink becomes idle(I didn't
> touch totem, so totem should keep playing back).
Update:

We've found a way the can reproduce the problem more quickly on our product:
1. do audio playback
2. alsamixer, select 'Master', press 'm' and hold for a while.

Then release 'm', playback corrupts(sounds similar to
http://dev.lemote.com/files/upload/software/PA-apc/corrupted_sound.ogg).
I notice the following in PA daemon log:
( 439.779|  55.236) D: [alsa-sink][modules/alsa/alsa-sink.c:1261
sink_get_volume_cb()] Read hardware volume: 0:  78% 1:  78%
([0x31a4e488])
( 439.780|   0.000) D: [alsa-sink][modules/alsa/alsa-sink.c:1266
sink_get_volume_cb()]                in dB: 0: -6.40 dB 1: -6.40 dB
([0x31a4e488])
( 439.781|   0.001) I:
[pulseaudio][modules/module-device-restore.c:723 subscribe_callback()]
Storing volume/mute for device+port
sink:alsa_output.pci-0000_00_14.2.analog-stereo:analog-output.
([0x7f891270])
( 439.782|   0.001) D: [alsa-sink][modules/alsa/alsa-sink.c:1607
process_rewind()] Requested to rewind 65536 bytes. ([0x31a4e9d8])
( 439.782|   0.000) D: [alsa-sink][modules/alsa/alsa-sink.c:1630
process_rewind()] Limited to 11248 bytes. ([0x31a4e9d8])
( 439.783|   0.000) D: [alsa-sink][modules/alsa/alsa-sink.c:1633
process_rewind()] before: 2812 ([0x31a4e9d8])
( 439.783|   0.000) D: [alsa-sink][modules/alsa/alsa-sink.c:1641
process_rewind()] after: 2812 ([0x31a4e9d8])
( 439.783|   0.000) D: [alsa-sink][modules/alsa/alsa-sink.c:1649
process_rewind()] Rewound 11248 bytes. ([0x31a4e9d8])
( 439.783|   0.000) D: [alsa-sink][pulsecore/sink.c:935
pa_sink_process_rewind()] Processing rewind... ([0x31a4e998])
( 439.783|   0.000) D: [alsa-sink][pulsecore/sink.c:3617
pa_sink_volume_change_rewind()] latency = 632 ([0x31a4e928])
( 439.784|   0.000) D: [alsa-sink][pulsecore/sink-input.c:984
pa_sink_input_process_rewind()] Have to rewind 11248 bytes on render
memblockq. ([0x31a4e940])
( 439.784|   0.000) D: [alsa-sink][pulsecore/source.c:864
pa_source_process_rewind()] Processing rewind... ([0x31a4e958])

I guess it is 'rewind' that cause the problem? What does rewind do?
Why we need rewind here?

BTW, PA has module-device-restore and module-stream-restore, dose that
means we don't need alsa-restore.service/store stuffs? What is the
difference between device-restore and stream-restore?



----
Regards,
cee1

Re: Adjust volume may cause audio playback corruption

[Clemens Ladisch]

cee1 wrote:
> We've found a way the can reproduce the problem more quickly on our product:
> 1. do audio playback
> 2. alsamixer, select 'Master', press 'm' and hold for a while.
>
> Then release 'm', playback corrupts(sounds similar to
> http://dev.lemote.com/files/upload/software/PA-apc/corrupted_sound.ogg).

Is the output supposed to be playing or muted at this time?

This appears to be a problem with PA's volume handling.
It might be caused by incorrect dB volume information of the HDA codec,
or by a bug in PA.

> What does rewind do? Why we need rewind here?

It allows to rewrite already written parts of the audio buffer; it's used
to apply the new volume to samples that have not yet been actually played.


Regards,
Clemens

Re: Adjust volume may cause audio playback corruption

[cee1]

[-- Attachment #1.1: Type: text/plain, Size: 899 bytes --]

在 2012年5月18日星期五，Clemens Ladisch 写道：

> cee1 wrote:
> > We've found a way the can reproduce the problem more quickly on our
> product:
> > 1. do audio playback
> > 2. alsamixer, select 'Master', press 'm' and hold for a while.
> >
> > Then release 'm', playback corrupts(sounds similar to
> > http://dev.lemote.com/files/upload/software/PA-apc/corrupted_sound.ogg).
>
> Is the output supposed to be playing or muted at this time?

Playing


>
> This appears to be a problem with PA's volume handling.
> It might be caused by incorrect dB volume information of the HDA codec,
> or by a bug in PA.
>
> > What does rewind do? Why we need rewind here?
>
> It allows to rewrite already written parts of the audio buffer; it's used
> to apply the new volume to samples that have not yet been actually played.
>
>
> Regards,
> Clemens
>


-- 
Regards,

- cee1

[-- Attachment #1.2: Type: text/html, Size: 1393 bytes --]

[-- Attachment #2: Type: text/plain, Size: 186 bytes --]

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Re: Adjust volume may cause audio playback corruption

[cee1]

2012/5/18 cee1 <fykcee1@gmail.com>:
> 在 2012年5月18日星期五，Clemens Ladisch 写道：
>
>> cee1 wrote:
>> > We've found a way the can reproduce the problem more quickly on our
>> > product:
>> > 1. do audio playback
>> > 2. alsamixer, select 'Master', press 'm' and hold for a while.
>> >
>> > Then release 'm', playback corrupts(sounds similar to
>> > http://dev.lemote.com/files/upload/software/PA-apc/corrupted_sound.ogg).
>>
>> Is the output supposed to be playing or muted at this time?
>
> Playing
Seems something to do with process_rewind(modules/alsa/alsa-sink.c), I
tried commenting out snd_pcm_rewind block in process_rewind() and set
out_frames=0 or out_frames=in_frames, the problem seems gone.

A bug in snd_pcm_rewind()/driver?



----
Regards,
cee1
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Re: Adjust volume may cause audio playback corruption

[cee1]

[-- Attachment #1: Type: text/plain, Size: 2078 bytes --]

2012/5/18 cee1 <fykcee1@gmail.com>:
> 2012/5/18 cee1 <fykcee1@gmail.com>:
>> 在 2012年5月18日星期五，Clemens Ladisch 写道：
>>
>>> cee1 wrote:
>>> > We've found a way the can reproduce the problem more quickly on our
>>> > product:
>>> > 1. do audio playback
>>> > 2. alsamixer, select 'Master', press 'm' and hold for a while.
>>> >
>>> > Then release 'm', playback corrupts(sounds similar to
>>> > http://dev.lemote.com/files/upload/software/PA-apc/corrupted_sound.ogg).
I've written a small program[1] that will let PA mute/unmute repeatedly.

I find the problem is something to do with rewind_safeguard, If I
adjust rewind_safeguard to eighth of the original value, it can also
be easily reproduced through pa-mute-test.c on the AMD turion 64 x2
board in ubuntu 12.04:
--- a/src/modules/alsa/alsa-sink.c
+++ b/src/modules/alsa/alsa-sink.c
@@ -86,8 +86,8 @@

 #define VOLUME_ACCURACY (PA_VOLUME_NORM/100)  /* don't require volume
adjustments to be perfectly correct. do

-#define DEFAULT_REWIND_SAFEGUARD_BYTES (256U) /* 1.33ms @48kHz, we'll
never rewind less than this */
-#define DEFAULT_REWIND_SAFEGUARD_USEC (1330) /* 1.33ms, depending on
channels/rate/sample we may rewind more
+#define DEFAULT_REWIND_SAFEGUARD_BYTES (32U) /* 1.33ms @48kHz, we'll
never rewind less than this */
+#define DEFAULT_REWIND_SAFEGUARD_USEC (166) /* 1.33ms, depending on
channels/rate/sample we may rewind more t

 struct userdata {
     pa_core *core;

Should we calculate limit_nbytes considering tsched_watermark?
e.g.(which works on our platform)
@@ -1614,7 +1614,7 @@ static int process_rewind(struct userdata *u) {
     unused_nbytes = (size_t) unused * u->frame_size;

     /* make sure rewind doesn't go too far, can cause issues with DMAs */
-    unused_nbytes += u->rewind_safeguard;
+    unused_nbytes += u->tsched_watermark;

     if (u->hwbuf_size > unused_nbytes)
         limit_nbytes = u->hwbuf_size - unused_nbytes;


----
[1]. See pa-mute-test.c in attachment, using build.sh to build it.


Regards,
-- cee1

[-- Attachment #2: pa-mute-test.c --]
[-- Type: text/x-csrc, Size: 1350 bytes --]

#include <glib.h>
#include <pulse/pulseaudio.h>
#include <pulse/glib-mainloop.h>

#define INTERVAL 125
#define TEST_NR  ((1000/INTERVAL)*3600*72UL)

struct context{
	pa_context *pa_cxt;
	GMainLoop *main_loop;
};

gboolean set_mute_unmute(struct context *cxt)
{
	static gboolean mute = TRUE;
	static gint count = 0;
	pa_operation *o;

	mute = !mute;
	count++;

	o = pa_context_set_sink_mute_by_index(cxt->pa_cxt, 0, mute, NULL, NULL);
	if (o == NULL) {
		g_warning ("pa_context_set_sink_mute_by_index() failed: %s", pa_strerror(pa_context_errno(cxt->pa_cxt)));
		g_main_quit(cxt->main_loop);
		return FALSE;
	} 

	if (count == TEST_NR) {
		g_print("Max test number(=%lu) reached, quit.\n", TEST_NR);
		g_main_quit(cxt->main_loop);
		return FALSE;
	}

	g_print("\r%10d:\tset to %6s", count, mute ? "mute":"unmute");
	pa_operation_unref(o);
	return TRUE;
}

int main()
{
	struct context cxt;
	pa_glib_mainloop *pa_main_loop;
	int r;

	pa_main_loop = pa_glib_mainloop_new(NULL);
	cxt.pa_cxt = pa_context_new(pa_glib_mainloop_get_api(pa_main_loop), "mute-automute-test"); 
	cxt.main_loop = g_main_loop_new(NULL, FALSE);

	r = pa_context_connect(cxt.pa_cxt, NULL, 0, NULL);

	if (r) {
		g_print("Failed to connect PA server.\n");
		exit(3);
	}

	g_timeout_add(INTERVAL, (GSourceFunc) set_mute_unmute, &cxt);

	g_main_loop_run(cxt.main_loop);

	return 0;
}

[-- Attachment #3: build.sh --]
[-- Type: application/x-sh, Size: 181 bytes --]

[-- Attachment #4: Type: text/plain, Size: 0 bytes --]

Re: Adjust volume may cause audio playback corruption

[cee1]

Hi,

2012/5/18 cee1 <fykcee1@gmail.com>:
> 2012/5/18 cee1 <fykcee1@gmail.com>:
>> 在 2012年5月18日星期五，Clemens Ladisch 写道：
>>
>>> cee1 wrote:
>>> > We've found a way the can reproduce the problem more quickly on our
>>> > product:
>>> > 1. do audio playback
>>> > 2. alsamixer, select 'Master', press 'm' and hold for a while.
>>> >
>>> > Then release 'm', playback corrupts(sounds similar to
>>> > http://dev.lemote.com/files/upload/software/PA-apc/corrupted_sound.ogg).
>>>
>>> Is the output supposed to be playing or muted at this time?
>>
>> Playing
> Seems something to do with process_rewind(modules/alsa/alsa-sink.c), I
> tried commenting out snd_pcm_rewind block in process_rewind() and set
> out_frames=0 or out_frames=in_frames, the problem seems gone.
>
> A bug in snd_pcm_rewind()/driver?
Some questions about rewind :-)
1. When rewind happens, it is possible to go into underrun, right?
2. The hardware doesn't know control->appl_ptr, it will go through a
buffer size and then wrap back, go through the buffer again?
3. About substream->ops->pointer, in HDA, it was implemented by
position buffer. Is it an atomic operation of update(by HDA
controller) /read(by driver)?
4. [alsa-libs] snd_pcm_mmap_commit() -> snd_pcm_hw_mmap_commit(),
which will forward pcm->appl.ptr(and wrap back if is bigger than
pcm->boundary) and then pass the new appl.ptr to kernel through
SNDRV_PCM_IOCTL_SYNC_PTR ioctl.
In kernel side, it will assign pcm->appl.ptr to control->appl_ptr directly.

The question is in alsa-libs appl_ptr stays in [0, pcm->boundary),
but in kernel side appl_ptr stays in [0, runtime->boundary),  will it
have problem if pcm->boundary != runtime->boundary? For example,
sometimes kernel is 64bits but the userland is 32bits, then the width
of 'long' in kernel will not be equal to width of 'long' in userland
on some platform.



-- 
Regards,

- cee1
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