Shortly before I left on vacation, I updated my system software and discovered a truly annoying bug. The upgraded system would boot normally, I could unlock the hard drive, but a few seconds after logging in the laptop screen would go black. The external monitor continued to work and sleeping the system and waking it would bring back the laptop screen — for a few seconds, after which it would go black again. I found no telltale log entries, nobody else seemed to be reporting a similar problem online, and posting to the Framework forum yielded some ideas but none panned out.
I tried booting to the kernel I was running prior to the update (Linux 6.12.9-200.fc41.x86_64) and the problem went away. Since I was leaving to go to a kind of remote campsite with intermittent internet access, I didn’t want to damage the system further and just had to remember to always select the older kernel when rebooting. I did try installing a beta kernel (.13) but it didn’t help.
Upon my return, I had more time to dig into it. It was an odd problem, because the screen didn’t go black until some significant number of seconds after logging in, so it didn’t seem to be a driver problem or a crash, and the logs backed that up.
After looking around at a lot of old posts, I found that the plasma-powerdevil service seemed a likely candidate: it is power management, and might be simply turning the brightness of the internal display to zero. I found a post that described this method for preventing powerdevil (a likely name for a glitch-inducing service if ever there was one!) from dimming the internal display:
-""-.,,.-""-.,,.-""-.,,.-""-.,,.-""-.,,.-""-.,.-""-”
execute the terminal command
systemctl --user edit plasma-powerdevil.service
and under the line that says “### Anything between here and the comment below will become the contents of the drop-in file” add…
[Service]
Environment="POWERDEVIL_NO_DDCUTIL=1"
save the file and type
systemctl --user restart plasma-powerdevil.service
to restart plasma
-""-.,,.-""-.,,.-""-.,,.-""-.,,.-""-.,,.-""-.,.-""-”
That seems to have fixed the problem, at the possible cost of disabling display dimming.
Armed with a workaround, I’m now going to try updating to the latest kernel release (.15) and see what happens. With luck, I’ll be able to back out the workaround when using the new kernel.
addendum 20250221@19:09
Sigh. Not only does the latest kernel release not solve the black screen problem, but the above workaround doesn’t work either. Apparently, I just got “lucky” and the glitch didn’t show up when I was testing it. For now, I’ve got a laptop that won’t work without an external display. Bummer.
Fortunately, the configuration change I made to keep more older kernels seems to have worked, so I can still boot into the .9 kernel and keep working.
—2p