Since one or two weeks ago, my display refuses to wake up from sleep. The symptoms are that pressing keys can wake up keyboard, mouse, but the display seems to try to wake up but then says “no signal input”.
Using ctrl+alt+f1 can bring up the display though. Then login and use
loginctrl unlock-session 3
, ctrl+d, ctrl+alt+f7 I can get back to my desktop.
In case you don’t already know the system’s name for your connection, run:
xrandr | grep conn | grep -v disc
Use the connection name, e.g. HDMI-1, this way:
xrandr --output HDMI-1 --auto
from Alt-F2 (run command) or via a script. If it works to wake up your display, assign it to a hotkey for easy use when necessary.
An idea that could possibly avoid the issue: disable KScreen2 in autostart. 5.26 has some disappointing regressions noted upstream resulting from trying to fix various related display issues represented by or related to this upstream bug.
Following Alt-F2 you could at least to try typing it blindly for testing to see if it does the job.
I assume I should run
xrandr --output HDMI-1 --auto
when display doesn’t wake up and I type it in another tty session? If so it doesn’t work as it returns “can’t open display”.
From a vtty you must make the display explicit: xrandr --display :0 --output HDMI-1 --auto. Whether it would actually do anything that way I don’t know, but at least it doesn’t generate an error message doing that here.
BTW, I find that using “ctrl+alt+f7” to wake up display and login is the fastest route.
That’s fairly simple. If the xrandr sequence would work, assigning it to a two-key hotkey would just be quicker/easier, and avoid modeswitching that occurs going to a vtty and back.
I hope this bug gets fixed soon and I won’t bother to create a script to test it out. Also just want to correct my previous post, I need to ctrl+alt+f1 to wake up the display, then ctrl+alt+f7. Going directly to tty7 doesn’t work.
Vtty7 is where most X sessions run. Some run on 1 (e.g. GDM/Gnome on Fedora), some on 2 or 8 (sessions beyond the initial), but traditionally and mostly 7. Thus, Ctrl-Alt-F7 is null for the purpose of switching away from SDDM/Plasma on 7 to a text login screen on any other to try to wake up the display, before switching back to Plasma with Alt-F7.