4.18.0-rc6 amdgpu framebuffer problems with DisplayPort
Submitted by LD
Assigned to Default DRI bug account
Created attachment 140848
combined kernel dmesg for two boot sessions, one in 4.17.0 and the other in 4.18.0-rc6
On kernel 4.17.0, amdgpudrmfb functions correctly; taking the fb from efifb
On kernel 4.18.0-rc6 (and previous), the framebuffer proper doesn't start; monitor doesn't get a valid display signal. If I log in and blind-start a Wayland compositor (sway in my case), the display gets a desktop and things work normally. Once I exit out back to FB, the display is blanked.
Everything works normally if I connect the monitor with HDMI instead.
This was a problem with 4.18.0-rc5 as well. I was pointed to the patch at https://lists.freedesktop.org/archives/amd-gfx/2018-July/023920.html and applied it to 4.18.0-rc5, but it had no effect on behavior.
Monitor: Acer XR341CK
Attachment 140848, "combined kernel dmesg for two boot sessions, one in 4.17.0 and the other in 4.18.0-rc6":