On Fri, Oct 09, 2015 at 04:28:10PM +0100, Russell King - ARM Linux wrote:
I think we should set capabilities based on the sink capabilities. And these should be set after reading the ELD. We want to do that when stream is opened and we query ELD and set the constarinats based on ELD. I have not added that code but this was the idea and was planned to come after this
Note that there's sound/core/pcm_drm_eld.c which should help you with that. Please help to improve it if it doesn't meet your needs - it's a helper precisely to set the constraints based on ELD.
It tries to find the best fit of sample rate vs channels given a ELD array of SADs.
That looks great. Yes I will use this and enhance it wherever required. It makese sense to keep adding there rather than in driver
So we have discussed this with Takashi and the general idea is that we add a SW mechanism as well which will be based on i915 component framework to read ELD reliably from display driver
I think as a general idea all the hdmi audio drivers should rely on component interface generically to read ELD/ get notification (that was added recently). Today on audio we have i915 component interface and IMHO this should be made a generic audio-display component interface and used by all. The callbacks are not really HDA based. But I don't really know on other arch if that is doable or not...
Do you have a pointer to this work?
sound/hda/hdac_i915.c