Arch Linux

Technicus

Member

Registered: 2016-10-15

Posts: 31

Resolution Fail After Update

Hello,

Last night I updated my system after about three weeks.  The computer has an AMD FXF 580 installed.  There are three monitors connected through display ports. They are two Samsung B2330H monitors and one LG 29UM58-P.  The Samsung monitors support  1920 X 1080 resolution while the LS supports 2560 X 1080.

Prior to the update the system was able to set the resolution for the LG to 2560 X 1080.  It was a little unstable at boot, but after starting an X11 session it worked fine.  After update the resolution is limited to 1920 X 1080.

I tried to add the resolution myself by following Arch Wiki Troubleshooting:

$ cvt 2560 1080
# 2560x1080 59.98 Hz (CVT) hsync: 67.17 kHz; pclk: 230.00 MHz
Modeline "2560x1080_60.00"  230.00  2560 2720 2992 3424  1080 1083 1093 1120 -hsync +vsync
$ xrandr --newmode "2560x1080_60.00"  230.00  2560 2720 2992 3424  1080 1083 1093 1120 -hsync +vsync
$ xrandr --addmode DisplayPort-1 2560x1080_60.00

When I attempted to switch to the resolution I added it failed:

$ xrandr --verbose --output DisplayPort-1 --mode 2560x1080_60.00 && sleep 5 && xrandr --output DisplayPort-1 --mode 1920x1080
crtc 1: 2560x1080_60.00  59.98 +1920+0 "DisplayPort-1"
xrandr: Configure crtc 1 failed
crtc 0: disable
crtc 1: disable
crtc 2: disable
crtc 3: disable
crtc 4: disable
crtc 5: disable
screen 0: revert
crtc 0: revert
crtc 1: revert
crtc 2: revert
crtc 3: revert
crtc 4: revert
crtc 5: revert

I'm out of ideas, and I'm running out of patients.  Any suggestions about how I could resolve this problem?  Thanks.

Links:
Samsung B2330H
LG 29UM58-P
AMD FXF 580
Arch Wiki Troubleshooting

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,248

Re: Resolution Fail After Update

There are some known issues with the DC stack, try to disable it by appending your kernel command line with

amdgpu.dc=0

Technicus

Member

Registered: 2016-10-15

Posts: 31

Re: Resolution Fail After Update

Alright, it's back to its previous behavior.  Will you tell me more about the DC stack?  I have no idea what that is.

Is this considered solved?  It seems like something else is majorly wrong that needs to be evaluated.  Thanks V1del.

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,248

Re: Resolution Fail After Update

It's primarily required for HDMI/DP audio and some other display features, you can read through e.g. Phoronix's coverage for more info: https://www.phoronix.com/scan.php?page= … =AMDGPU+DC

It's definitely an issue that should be reported to the kernel maintainers but with something as widespread as this current issue there are likely reports on it already, so if this is your intention you should search the kernel bugtracker if it hasn't already been reported.

If you, however consider it resolved from this thread's point of view you are free to mark it as such.