I am having this weird problem, sometimes when I boot my system SDDM takes no input.
When it happens I can’t input anything using the keyboard or the mouse. At the same time can move the mouse cursor around and also I can switch to another tty, it feels like SDDM is unresponsive.
I also compared the logs of SDDM when it hangs vs a normal boot. I couldn’t find any difference.
I already deleted ~/.Xauthority, like some threads suggested, unfortunately without success.
I have the same issue with my main computer at home: When I boot the machine from a cold state (complete power down: unplugged, or power failure, or rear power switch was turned “Off”), if i attempt to boot normally, then immediately after logging in, I get one of these:
Display alternates between all-white and all black screens, 5sec each, forever; mouse and keyboard do nothing
Display looks normal, but mouse and keyboard do nothing.
It’s been doing that for months. Maybe SDDM, or maybe something else. I never found a solution from within Manjaro, but I did find a work-around that works every time: When the BIOS password screen comes up (I have that enabled) I push the front panel “Reset” button. Then the second time the BIOS password screen pops up, I log-in to BIOS, then hit “Enter” on the Grub screen, then log-in normally on the GUI Manjaro Linux log-in screen, and everything works. Something not getting fully reset on power-up? Try pressing your front panel “Reset” button (if you have one) a few seconds after every power-up, and see if your problem goes away. (If no “Reset” button, long-press the front-panel “On/Off” button until the system shuts down, wait 10 sec, then short-press “On/Off”.) May not work (if your symptoms are from a different cause), but can’t hurt, so worth trying.
No quick fix here; but, for what it’s worth, I have also experienced what you describe:
Usually, after waiting 30 seconds, or similar, I was able to again enter text in the login screen inputs. What caused it, I don’t know; it was on an older machine with less resources; however, I suspect it was simply that background processes and/or support for applications starting at login had not yet finished loading. Using a keyboard and mouse (Logitech) with a wireless USB receiver probably added to the delay.