[alsa-devel] [PATCH 2/5] hda - allow up to 10 Azalia codecs

[Wu Fengguang]

On Wed, May 12, 2010 at 10:35:46PM +0800, Takashi Iwai wrote:
> At Wed, 12 May 2010 09:30:17 +0800,
> Wu Fengguang wrote:
> > 
> > Currently AZX_MAX_CODECS is defined to 8. Increase it to 10 in order to
> > support the HDMI device indices {3, 7, 8, 9}.
> 
> If I understand correctly, the codec slot number is basically
> independent from the PCM device number assigned.  Hence this change
> shouldn't be necessary unless you really have more than 8 codec
> chips.  Or will be such a high codec address expected soon on new
> Intel platforms?

You are right, it works without this patch. Sorry for the confusion!

> > The HD audio spec allows up to 14 codecs. So we are still within the
> > hardware capacity.
> 
> I thought this was at most 8, so I used the value 0x100 as a special
> bit flag for probe_mask module option :-<
> We'd need to change this if we extend the max codecs...

It may allow 15 codecs in fact. I get the max number from "Figure 32.
Codec Address Assignment Frame":

CODEC Samples Address ** Address 15 is reserved for
 0 1 2 3 ......... 14    link protocol purposes and
                         may not be assigned to
                         CODECs

And STATESTS has bits 14:0 allocated for "SDIN State Change Status Flags
(SDIWAKE)".

However we don't need to increase AZX_MAX_CODECS and probe_mask for now.

Thanks,
Fengguang