[Cbe-oss-dev] PS3 sound driver update

[Geoff Levand]

Geoff Levand wrote:
> Marc Bevand wrote:
>> The latest publicly released version of the snd_ps3pf ALSA sound driver
>> for playstation 3 can be found in the kernel source tree linux-20061208
>> published there [1] (derived from 2.6.16, as I understand it). Geoff Levand
>> has not yet integrated the driver into his git tree on kernel.org [3].
>> 
>> According to the very limited public documentation about the sound
>> chip available on [2], it looks like it probably supports AC3/DTS
>> passthrough however [1] does not implement this feature. I have
>> looked at the source code and am not very familiar with the ALSA API
>> but it seems that adding support for this feature would just require
>> the implementation of a new snd_kcontrol_new named "IEC958
>> Playback Default" whose purpose would be to set some control bits
>> in the frames sent over the S/PDIF output. This can probably be done
>> in only 100-200 lines of code.
>> 
>> I have 2 questions:
>> o Does Sony plan to add support for AC3/DTS passthrough in the near
>>   future ? It doesn't look like a complex task.
>> o When will snd_ps3pf be ported to the git tree [3] ?
>> 
>> [1]
>> ftp://ftp.kernel.org/pub/linux/kernel/people/geoff/cell/ps3-linux-distro-kit-20061208/src
>> [2] ftp://ftp.kernel.org/pub/linux/kernel/people/geoff/cell/ps3-linux-distro-kit-20061208/doc/LinuxKernelOverview.html
>> [3] git://git.kernel.org/pub/scm/linux/kernel/git/geoff/ps3-linux.git
>> 
> 
> Rasmus Rohde wrote:
>> I've been extending the PS3 sound driver to support 6 channel audio, but
>> I need a few details on how to DMA the extra channels.
>> 
>> Anybody know if there is documentation to be found publicly on this?
>> 
>> I think it would also be in the interest of many to get the driver
>> extended to support AC3/DTS pass-through. I'd be happy to look into this
>> as well.
> 
> Ranulf Doswell wrote:
>> I'm going to focus my attention on basic 2-channel sound support next
>> (although I'd really like to get 5-channel to DTS encoding happening
>> on an SPU soon!) so that I have the basic elements to start writing a
>> decent game.
> 
> 
> Hi all.
> 
> Just to give an update on PS3 sound support, the sound driver has been
> merged into the ALSA tree, so should go into the mainline kernel sometime
> soon.
> 
>   http://hg-mirror.alsa-project.org/alsa-kernel/rev/8c85fc05e574
> 
> The current driver supports only 2 channel PCM data. The hypervisor will
> allow 5 channel PCM and pass-through though.
> 
> Several people have expressed interest in enhancing the PS3 sound driver.
> The ps3-linux team currently has no plan add any new features or support.
> If anyone is working on any PS3 sound driver enhancements, or has some
> interest in collaborating on it, could you let us all know?

Just FYI,

PS3 sound pass-through mode was added to the mainline linux
kernel today.

commit 88e366217e8f75bd7eab64f4aa4ff9583070b0af
Merge: a1cf649... 975f6b0...
Author: Linus Torvalds <torvalds at linux-foundation.org>
Date:   Mon Oct 20 09:09:56 2008 -0700

    Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
      ALSA: ps3: Add support for SPDIF/HDMI passthru
      ps3: Add passthru support for non-audio streams
      ps3: Add ps3av_audio_mute_analog()

-Geoff