[Cbe-oss-dev] PS3 sound driver update

[Bradley, GT]

I'm interested in going forward with this.  (I wrote a longer response
but my web-mail ate it :(  )

Short story:  if I can get info on the chip interface, e.g.:  where is
the "SPOCS" register: which I believe has the magic bit that needs
setting for AC3 pass-through to work.

>From snd_ps3_reg.h:
/*
S/PDIF Audio Output Channel Channel Status
Setting Registers.
Configures channel status bit settings for each block
(192 bits).
Output is performed from the MSB(AO_SPDCS0 register bit 31).
The same value is added for subframes within the same frame.
 31            24 23           16 15            8 7             0
 +-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+
 |                             SPOCS                             |
AO_SPDCS
 +-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+
...
*/


I will also look into the video drivers as I've just discovered that
they also contain audio code.

GT


-----Original Message-----
From: Levand, Geoffrey 
Sent: Tuesday, July 10, 2007 12:36 PM
To: Marc Bevand
Cc: cbe-oss-dev at ozlabs.org; rohde at duff.dk;
ralferoo at users.sourceforge.net
Subject: PS3 sound driver update


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-dist
> ro-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?

-Geoff