displayport connected monitor doesn't initialize display

Submitted by Bret Towe

Assigned to Default DRI bug account

Link to original bug (#104205)

Description

I have a LG 29UB55-B 21:9 monitor connected via DisplayPort to a Radeon R7 370 card
after boot when xorg loads 99% of the time the monitor won't see a signal and goes to sleep
once its woken back up by its power button it sees the normal screen at its native res of 2560x1080

I also see I assume the same problem if i change resolution down to 1920x1080 its fine but switch back to 2560x1080 and screen goes to sleep with no signal
wake it back up and fine again at 2560

I see the below in dmesg:

[ 6.400479] [drm:radeon_dp_link_train [radeon]] ERROR clock recovery reached max voltage
[ 6.400523] [drm:radeon_dp_link_train [radeon]] ERROR clock recovery failed

kernel is 4.14.4 currently it's been going on since I got the monitor
I don't recall what version that was.

xorg is on 1.19.5
amdgpu driver is 1.4.0
also tried the radeon driver and acts same
haven't tried binary drivers

no errors in xorg log