Am 06.06.19 um 11:13 schrieb Ser, Simon: > On Tue, 2019-06-04 at 17:15 +0200, Christian König wrote: >> Am 04.06.19 um 17:05 schrieb Ser, Simon: >>> Hi, >>> >>> I'm trying to link ALSA playback devices and DRM connectors. In other >>> words, I'd like to be able to know which ALSA device I should open to >>> play audio on a given connector. >>> >>> Unfortunately, I haven't found a way to extract this information. I >>> know /proc/asound/cardN/eld* expose the EDID-like data. However by >>> looking at the ALSA API (also: aplay -l and -L) I can't find a way to >>> figure out which PCM device maps to the ELD. >>> >>> Am I missing something? >> Is that actually fixed on all hardware? Or do we maybe have some >> hardware with only one audio codec and multiple connectors? >> >>> If not, what would be the best way to expose this? >>> >>> - A symlink to the ALSA audio PCM device in >>> /sys/class/drm/cardN-CONNECTOR? >>> - A symlink to the DRM connector in /sys/class/sound/pcm*? >> If it's fixed than those two options sound sane to me. >> >>> - A DRM connector property? >> If it's configurable than that sounds like a good option to me. > I'm still not sure whether this is fixed on all hardware or not. Well from reading up on the thread I think the answer is that this is NOT fixed. At least from AMD hardware I know that the original R600 had only one audio codec which could be routed to multiple HDMI connectors at the same time. And I understand the reply about MST so that you can even have multiple streams over the same codec routed to different connectors. Christian. > > Ville, on this old Intel hw, is the single connector that gets the > audio configurable? > > Additional thought: since I need this for the IGT test suite I don't > really care how this info is exposed as long as it's exposed, but other > userspace programs (DEs) are probably interested in this information > too. This would allow users to actually have the name of the monitor in > the audio output selection UI. Having something that doesn't depend on > sysfs would be better for this. > > Would there be a way to expose some info about the monitor in the ALSA > API? > >> Anyway added our DC team, stuff like that is their construction site. >> >> Regards, >> Christian. >> >>> - Somehow expose the connector name via the ALSA API? >>> - Expose the connector EDID via ALSA? >>> - Other ideas? >>> >>> Thanks! >>> >>> Simon Ser >>> _______________________________________________ >>> dri-devel mailing list >>> dri-devel@xxxxxxxxxxxxxxxxxxxxx >>> https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
