Bad DisplayPort enumeration and wrong refresh rate with Hawaii chip
Submitted by pub..@..ril.me
Assigned to Default DRI bug account
Created attachment 143150
Xorg.0 log with DC off
I'm running Solus KDE with kernel 4.20.2 but I've had these issues since kernel 4.19. Here's the list of issues with AMDGPU DC enabled:
- With Solus' default kernel flags I have wrong DisplayPort enumeration, meaning that I get DisplayPort-1 when I turn on the computer, and then DisplayPort-2 when I get my monitor to sleep and then I wake it up.
- If I put my computer on sleep (suspension) and then wake it up, I cannot set a usable refresh rate. This means I actually get 40 Hz when I set 60, and 45 Hz when I set 74 (yeah, I have a bit of screen "overclocking". That's how I found DisplayPort enumeration is wrong).
- I get microstuttering, particularly noticeable when I drag windows around.
Now, all these issues are non existant if I set the amdgpu.dc=0 kernel flag. Also, DisplayPort number is DisplayPort-0 under any circumstances.
❯ inxi -G
Graphics: Device-1: AMD Hawaii PRO [Radeon R9 290/390] driver: amdgpu v: kernel
Display: x11 server: X.Org 1.20.3 driver: amdgpu,ati unloaded: fbdev,modesetting,vesa
renderer: AMD Radeon R9 200 Series (HAWAII DRM 3.27.0 4.20.2-107.current LLVM 7.0.0)
v: 4.5 Mesa 18.3.1
**Attachment 143150**, "Xorg.0 log with DC off":