[alsa-devel] [PATCH 0/30] ALSA: HDA VIA: patch series

[Robert Hancock]

On 10/11/2009 01:27 PM, Takashi Iwai wrote:
> At Sun, 11 Oct 2009 10:56:48 -0600,
> Robert Hancock wrote:
>>
>> On Sun, Oct 11, 2009 at 10:18 AM, Takashi Iwai<tiwai at suse.de>  wrote:
>>> At Sat, 10 Oct 2009 19:07:09 +0800,
>>> Logan Li wrote:
>>>>
>>>> Following patch series mainly includes:
>>>>   - support VT1718S, VT2002P, VT1812S, VT1716S, ...
>>>>   - support smart 5.1
>>>>   - add jack detection for VT1708
>>>>   - power saving functions
>>>
>>> Thanks for the patches.  They are all well formatted now.
>>>
>>> I applied your patches except for 17,
>>>         ALSA: HDA VIA: Add 2nd S/PDIF out for VT1708S and VT1702
>>> as Robert reported a regression.
>>>
>>> This is likely because of the behavior change by this patch.  Now
>>> the second SPDIF has to be specified manually with the explicit
>>> substream number.  This itself is fine, but I see the problem with
>>> pulseaudio, for example.  There is no good way to specify this substream
>>> automatically for PA with some symbols like "spdif" or "hdmi".
>>>
>>> This is basically a problem of the current ALSA core and HD-audio core
>>> implementation.  So, we should solve all together.
>>
>> Actually, the latest posted version didn't have the mixer problem I
>> had before (I haven't looked in detail at what was different). But I
>> agree using a different substream for a different output isn't ideal
>> since there's no way for software to detect that this is the case. Can
>> it be a separate PCM like hw:0,2 or something?
>
> It would work like hw:0,1,1.  But, this is exactly what I mentioned in
> the above.  The secondary SPDIF isn't specified as an intuitively
> selectable PCM device.

Well, if it was its own subdevice like hw:0,2 it would have some hope of 
being detected by HAL, PulseAudio, etc. If it's just a substream then I 
don't think that software can actually tell it's a separate output and 
not just a HW mixing-type stream, etc.

>
>> Hopefully VIA will also look into the SPDIF no-output problem I have
>> with VT1828S..
>
> What is the problem, specifically?

With the latest patch I do get the optical output lighting up and the 
receiver detects a PCM signal, but it seems to be just silence coming 
through. (In previous iterations the SPDIF digital converter wasn't 
being enabled automatically so it didn't get even that far.)