Opensuse - Can't configure RX580 for 5120x1440 resolution

English Hardware
1

I recently purchased a Samsung 49" monitor capable of 5120x1440 resolution. I have two computers connected to the monitor:

  1. A windows box at 5120x1440 using DisplayPort and is working at full resolution.
  2. An OpenSuse 15.4 LEAP Server using HDMI and is limited to 3480x2160.

The monitor has:

  1. 1 DisplayPort and
  2. 2 HDMI ports.

The OpenSuse RX580 has

  1. 2 DisplayPorts capable of 5120x1440
  2. 1 HDMI port capable of 3480x2160.

My solution was to utilize the RX580 DisplayPort to obtain the higher resolution. I bought an 8K DisplayPort to HDMI active adapter and an 8K HDMI cable. The active adapter is plugged into the RX580 GPU DisplayPort, then the 8K HDMI cable leads from the active adapter to HDMI-1 on the monitor. That done, I get a maximum resolution of 3480x2160 (same as I previously got using HDMI to HDMI).

Using xrandr, It appears the OpenSUSE driver does not recognize the higher resolution of the GPU DisplayPort. The highest resolution listed using xrandr is 3480x2160.

xrandr --output DisplayPort-0 --mode 5120x1440 results with the following error message: cannot find mode 5120x1440

I am not in a dire situation. All is functional at 3480x2160 but the higher resolution would be a great feature. Any thoughts on how to proceed?

2

You could try creating/using a custom display mode (refer links below)…

https://www.reddit.com/r/linux_gaming/comments/pnkykr/creating_a_custom_resolution/
https://wiki.archlinux.org/title/Xrandr#Adding_undetected_resolutions

If that works it can be made permanent.

3

Your first link did the trick. Thanks very much!

You also mentioned making it permanent – An internet search returned a wide variety of different instructions - Is the correct approach to add the commands to /etc/X11/xinit/xinitrc?

The commands I used are:
–newmode
–addmode
–output

Are all three command lines with the parameters required?

4

The commands need to be run as user, so you can add it as an autostart script upon user login.

5

That is correct.

6

You could add the commands to ~/.profile so that they get executed upon login.

7

Possibly you can use HDMI output from video card for that.