My Dell U2711 monitor on Display Port connection is competing for audio resources with my Onkyo TX-SR308 AV receiver.
This lead to very annoying times when I do not turn on my AV receiver before my monitor, leading to my sound device (AMD HD audio) switching to DP audio rather than HDMI audio. Only a system restart can I have my audio back. There is no way of switching the audio path between HDMI and DP. This has plagued me over 1 year and no one from AMD, despite repeated technical support queries, could help me.
I have tried EDID editing and removed the EDID information on audio support without luck.
Note that I cannot change my DP to DVI due to availability of ports on my video card, nor I can drive my monitor from HDMI, as U2711 is incapable of supporting HDMI with native resolution of 2560x1440. Attempt to use DP to DVI converters also fail as most of them, even active converters, do not support Dp to dual-link DVI at 2560x1440 resolutions.
Not sure. Have you looked in the Device Manager for a listing for DP Audio? If you see it, can you simply disable (not delete) it.
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Unfortnately no. AMD driver consolidates itself, regardless of interface, as AMD High Definition Audio device. It switches itself to HDMI and DP automatically base on order of interface detected and acts as a single audio device. There is no options in software to alter this behavior.
I was hoping somewhere in Dell monitor I can disable the audio so that the EDID information transmitted over one of the interface will not have audio support specified, which may overcome the issue. But as far as I can see there is none.
So if you go into the U2711 OSD (On Screen Display) - Audio and force it to HDMI, then power all three off (monitor, PC, AV receiver), then power the PC on first, monitor second, and AV receiver third, the monitor automatically changes its Audio setting from HDMI to DP. Is that correct?
If yes, why not power them on in this order (AV receiver, PC, monitor) ?
Firstly, there is no point of choosing between HDMI and DP audio in the monitor, as I don't use my monitor audio out. Choosing between them do not affect the behvaior of the audio driver. It's not the monitor which is changing audio source, it's the AMD HD audio driver.
The only solution is to power on in the correct order, which I have been doing. But every once in a while I forget. I don't get used to doing it since sometime I leave the AV receiver due to the profile resetting everytime I do so (I have to reenable the AV receiver as a display in control panel by duplicating a desktop onto it if turned off, otherwise no audio) and therefore I only have to turn on monitor.
The root cause lies in the fact that U2711 broadcasts EDID to both DP and HDMI saying it's capable as audio sink I wish there are ways to change EDID behavior.