Your best bet would be to avoid the dongle and use direct HDMI cable. What happens when you hotplug the projector to the GPU?
Does it show up in OS display settings or in Radeon Settings?
sorry I provided wrong information my HDMI cable is 10m long from PC to AV-Receiver and the other HDMI cable from AV-Receiver to Projector is 10m long too, so together 20m, but i think the AV-Receiver refreshes the signal
Iam getting the same problem when the projector is hotpluged to my gpu -> no picture but projector is detected as HDMI device in Radeon Settings.
The projector attempts to show a picture but didnt get it to work...
I think the problem is the lenght of the HDMI cable, mybe the HDMI port doesnt provide enoth power for the cable to transport the signal to my AV-Receiver?
But why is than the AMD DVI Adapter working? And only this one is working! (other cheep adapters without sound functionality didnt work)
This problem is really curious but with my HD6950 i had the same problem and so long its working with the AMD DVI Adapter iam fine with this workaround.
But my second problem with the AMD Audio Device is really annoying