Single display unable to set 5120x1440 resolution

Question

I was running Ubuntu 19.04 with a Philips 499P9H 5k monitor that was running at 5120x1440 at 70Hz. Today I upgraded to Ubuntu 19.10 and can now only run the monitor at 3840x1080 at 60Hz.

The option for 5120x1440 is available however when I select it I just get the same 3840x1080.

I remember previously I had to run X -configure and copy the config to /etc/X11/xorg.conf. However the file still existed from before and even after running that again there was no difference and I can still only run at 3840x1080.

The monitor is connected via display port and I the GPU is an Intel HD Graphics 530. As I mentioned, this did work before the upgrade but doesn't anymore.

Screenshot of xrandr listing the supported modes:

Answer 1

For those finding this now, these steps worked on Intel Iris Graphics 540 and 5120x1440 on a Samsung G9.

Modifying the commands used here - How do I change the screen resolution using Ubuntu command line?

Create a mode string for 5120x1440 at 30HZ (I'm using HDMI and HDMI 1.4 supports 30HZ only at 5120x1440)

$ cvt 5120 1440 30
5120x1440 29.96 Hz (CVT) hsync: 43.98 kHz; pclk: 292.75 MHz
Modeline "5120x1440_30.00"  292.75  5120 5360 5888 6656  1440 1443 1453 1468 -hsync +vsync

Copy everything after Modeline and for xrandr, like this:

$ sudo xrandr --newmode "5120x1440_30.00" 292.75  5120 5360 5888 6656  1440 1443 1453 1468 -hsync +vsync 

Find the current display, in my case HDMI-1 is returned:

$ xrandr | grep -e " connected [^(]" | sed -e "s/\([A-Z0-9]\+\) connected.*/\1/"
HDMI-1

Add the mode to the display (replace HDMI-1 with whatever was returned from the last command):

$ sudo xrandr --addmode HDMI-1 5120x1440_30.00

You can now change the resolution to the new mode in the graphics settings (or change by command line).