Re: [alsa-devel] Need your advice: Add a new communication inteface between HD-Audio and Gfx drivers for hotplug notification/ELD update

Alex Deucher
2014-01-24T17:38:20Z

On Fri, Jan 24, 2014 at 3:23 AM, Raymond Yau
<superquad.vortex2@gmail.com> wrote:
>
>>
>> >> And I have a question: how to assure the audio/gfx client find its
>> >> right peer?
>> >> On a x86 platform, there can be an integrated GPU and an discrete GPU.
>> >> So there can be two audio controllers and two GPUs.
>> >> We need to assure audio controller find the proper GPU, and vice versa.
>> >> Maybe we need the peer audio/gfx to register with a same identifier
>> >> (something like vendor ID) for peering.
>> >
>> > Yes, it's an open issue. So far, the binding with vga_switcheroo is
>> > done by a rough guess with PCI ID.
>>
>> Yeah, I guess we need platform/bus specific hints.
>
>
> http://www.displayport.org/cables/driving-multiple-displays-from-a-single-displayport-output/
>
> How do the audio driver know which displays when a single displayport output
> can drive multiple displays ?

Generally, there is a back channel between the display hardware and
the audio hardware.

Alex