Created attachment 156763 [details] kscreen-console SUMMARY At some point after connecting an external monitor via usb-c DP passthrough, the primary monitor (on the laptop) becomes completely black. When manually dragging a window over to the monitor, it displays, but then flickers endlessly (like when you win at solitare) STEPS TO REPRODUCE 1. Log in with only one monitor (primary = laptop monitor) 2. Attach an external monitor via USB-C DP passthrough 3. ?? Still investigating to try to understand exactly when the bug triggers. I'm pretty sure it's not immediately on device attach 4. OBSERVED RESULT * See the attached video for the screen flickering * Restarting plasmashell does NOT fix the behavior kscreen-doctor output: > Output: 1 eDP-1 enabled connected priority 1 Panel Modes: 0:2256x1504@60*! 1:2256x1504@48 2:1600x1200@60 3:1280x1024@60 4:1024x768@60 5:1920x1200@60 6:1280x800@60 7:1920x1080@60 8:1600x900@60 9:1368x768@60 10:1280x720@60 Geometry: 0,549 2256x1504 Scale: 1 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: Automatic > Output: 2 DP-1 enabled connected priority 2 DisplayPort Modes: 0:3840x2160@60*! 1:3840x2160@30 2:1920x2160@60 3:2560x1440@60 4:1920x1200@60 5:2048x1080@24 6:1920x1080@60 7:1920x1080@60 8:1920x1080@60 9:1920x1080@60 10:1920x1080@60 11:1920x1080@50 12:1920x1080@50 13:1920x1080@24 14:1920x1080@24 15:1600x1200@60 16:1600x900@60 17:1280x1024@75 18:1280x1024@60 19:1152x864@75 20:1280x720@60 21:1280x720@60 22:1280x720@50 23:1024x768@75 24:1024x768@60 25:800x600@75 26:800x600@60 27:720x576@50 28:720x576@50 29:720x480@60 30:720x480@60 31:720x480@60 32:720x480@60 33:640x480@75 34:640x480@60 35:640x480@60 36:640x480@60 37:720x400@70 38:1600x1200@60 39:1280x1024@60 40:1024x768@60 41:2560x1600@60 42:1280x800@60 43:3200x1800@60 44:2880x1620@60 45:2560x1440@60 46:1920x1080@60 47:1600x900@60 48:1368x768@60 49:1280x720@60 Geometry: 2256,0 3840x2160 Scale: 1 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: Automatic kscreen-console hangs when running, not sure if that's expected, but I've attached the output to the bug report. EXPECTED RESULT SOFTWARE/OS VERSIONS Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.27.1 KDE Frameworks Version: 5.103.0 Qt Version: 5.15.8 ADDITIONAL INFORMATION
Created attachment 156764 [details] screen recording of display flickering
Some more debugging notes: Pressing ctrl-alt-shift-f1 goes back to SDDM, which does display on the primary monitor. However, it doesn't appear responsive to mouse clicks or anything * Opening a new virtual tty (e.g. ctrl-alt-shift-f2) is functional on the primary monitor * Unplugging the monitor doesn't help, it stays in a black screen * Plugging the monitor back in only makes it worse, now both monitors have the screen flickering behavior. * It does not repro immediately after plugging in the monitor, but only sometime afterwards. Will try to figure out what causes the bug to trigger
Also take a look at https://bugs.kde.org/show_bug.cgi?id=466489 as it appears that KWin was crashing around the time I took the screen recording. I noticed KWin::PointerInputRedirection::updateAfterScreenChange is in that callstack, maybe it's related?
This just means that your plasmashell crashed. Getting a backtrace there could be useful. Does this mean that the other screen shows it properly?
(In reply to Aleix Pol from comment #4) > This just means that your plasmashell crashed. Getting a backtrace there > could be useful. > > Does this mean that the other screen shows it properly? I don't have any record of it in my coredumpctl (and also restarting plasmashell didn't fix the issue). And yes, if I drag the window to the external monitor, it displays without issue
Are you on Wayland or X11? Does it happen on both, or just one?
Is this still happening for you on Plasma 6?
No repro on KDE 6