External Monitor Issues

Ask Fedora
1

Hi,

I run into 2 issues on my System76 Lemur Pro (lemp10) with Fedora Silverblue 37 while working with my LG 27UN880 4K monitor:

  1. When I unplug the monitor’s USB-C cable, it cannot detect that the monitor is unplugged so that it’d adjust the screen, applications etc. I cannot close the lid to make my computer sleep when this occurs. When I do, it either works fine or locks up with the fans spinning like crazy. If I restart my computer without the monitor is plugged in, closing the lid works fine.

1a) I recently realized that the same sleep issue happens when I start using my bluetooth peripherals (keyboard & mouse)

  1. Normally the monitor works just fine with a refresh rate of 60 Hz. After I wake my computer from sleep with the monitor plugged in, the refresh rate drops to 30 Hz and it cannot be changed back to 60 Hz until I restart or enforce the monitor to switch to another Displayport Version (from 1.2 to 1.4 and wise versa)

I’ve had this 2nd issue with Pop!_OS and now Fedora Silverblue so I think it’s some kernel issue.

The first issue started after an upgrade on F35 but not sure where and it still happens after the upgrade to F37. It’s really annoying because I can’t just unplug my computer and continue on the go. Anyone else having this issue?

2

I wanted to test the first issue today and here are my findings:

  • Plugged monitor via HDMI, font rendering is not good as USB-C
  • Unplugging the monitor works as expected
  • Plugged monitor via USB-C, unplugging it works as expected
  • Sleep doesn’t work when bluetooth peripherals are connected
  • Disconnected bluetooth peripherals, sleep works
1 Like
3

Can you confirm that your HDMI Interface on the monitor is the newer HDMI Standard already and that your cable is compatible with the newer HDMI version?