[alsa-devel] HDMI on HDA device=3

David Henningsson david.henningsson at canonical.com
Tue Nov 9 16:16:41 CET 2010

On 2010-11-09 15:58, Jaroslav Kysela wrote:
> On Tue, 9 Nov 2010, David Henningsson wrote:
>> I have seen a few HDMIs which share the HDA controller with the onboard
>> sound card, but the codecs are different, e g the onboard one is at
>> address #0 and the HDMI is at address #3 - or even #3, #7, #8 and #9 in
>> some cases.
>> Now, if the user specifies the device string hdmi:x (where x is card
>> name/number), I'd like it to kind of autodetect this and use DEV=3
>> instead of DEV=0, and without breaking the cards where the hdmi is a
>> separate card with a codec at address #0. However, it still seems like
>> the device is at DEV=3 somehow.
>> Now, looking at /usr/share/alsa/cards/HDA-Intel.conf, I notice that
>> there are entries HDA-Intel.pcm.hdmi.0 which sets DEV=3, so it seems
>> like someone already thought of this. However, just using "hdmi:x" does
>> not trigger "DEV=3". I'm still not grepping all of the alsa lisp
>> architecture stuff, so could someone explain to me how the
>> HDA-Intel.pcm.hdmi.0 entry relates to the "hdmi:x" alsa device string?
> It's not about a lisp (this portion of code is not used at all). It's
> about the (partly) dynamic alsa-lib configuration.

Ok, thanks for the clarification.

> Use always indexes from 0.. (hdmi:0,0 etc..) Fist number is card number,
> second number is device number (which is logical device number mapped to
> different physical device number in case when HDA card contains both
> analog and HDMI sections).
> If you read HDA-Intel.conf, you'll get this device mapping (logical,
> physical):
> 0 -> 3
> 1 -> 7
> 2 -> 8
> 3 -> 9
> Perhaps, something does not work correctly?

Hmm, this is a little confusing. Do all these mean the same thing, and 
do they all correspond to the logical device number?


And would hdmi:x and hdmi:x,0 be the same thing?

And if all these correspond to the logical device number, is there any 
way you can specify the physical device number directly in the connect 

David Henningsson, Canonical Ltd.

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