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Dave
Asked: 2022-06-07 19:00:50 +0800 CST

KDE Plasma suddenly not showing display resolution above 1080p

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I've been trying to get this back all night but I've failed so I thought I'd come here and ask.

I was moving my machine (HP Z240 with standard Intel graphics) running Ubuntu Studio 21.10 that was running at 2K resolution. Had a mishap with the DisplayPort cable. Plugged another in and the highest resolution I'm offered is 1080p. Used another cable bought only a month ago, still 1080p.

I did some fiddling with xrandr and for a short while I had 4K running at a very low refresh rate (the original reason for choosing 2K), so at least i know the cable's not the problem. Where have the other resolutions gone? And how can I get them back?

HDMI-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 1872mm x 1053mm
   1920x1080     60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98  
   1920x1080i    60.00*   50.00    59.94  
   1680x1050     59.88  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1440x900      59.90  
   1280x800      59.91  
   1152x864      75.00  
   1280x720      60.00    50.00    59.94  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32  
   720x576       50.00  
   720x576i      50.00  
   720x480       60.00    59.94  
   720x480i      60.00    59.94  
   640x480       75.00    72.81    66.67    60.00    59.94  
   720x400       70.08

EDIT:

After I did some searching I found a way to decode the display's EDID file using read-edid. This gave me all the modes available for the display. I still don't understand why these are not being read by the system.

Anyway, I found the mode:

"Mode 1" 241.50 2560 2608 2640 2720 1440 1443 1448 1481 +hsync -vsync

which looked very similar to what I had been using. I renamed this mode and then created it as a new one using xrandr. It appeared in settings and allowed me to switch to it.

To make these changes permanent the only suggestion i've found is to run my xrandr script as a batchfile at startup. Is this the only way? And I still have no idea why the original settings are no longer shown.

display

0 Answers