so I have this oldish laptop I keep sitting around at my workplace for occasional internet, taking notes or printing a document:
Lenovo T400, Intel Core2 Duo T9400 with Intel Mobile 4 Series Integrated Graphics, running the integrated laptop screen as well as an external monitor. Original BIOS, not converted to libreboot yet.
Last time I used it (a few days back) I must have finished by running an update, as I was now greeted by a newly designed login screen. Guessing it was updated to Plasma 5.21.1 before last shutdown.
Plasma starts, I get the graphics login screen, then a black screen with some plasma logo and info text and finally the screen goes black with a mouse cursor.
By pressing F12 I get the Yakuake drop down terminal and from this I can start applications such as the Firefox I’m writing this in, or Dolphin etc.
Figured something must have happened with the last update I ran so I ran another pamac update from the command line and indeed it updated some more stuff, but the problem persisted (after reboot). Now pamac tells me “nothing to do”.
Hence, X-Windows support for the applications seems fine with full support for both screens, but no display of a usable desktop interface, nor wallpaper or anything else (just the mouse cursor).
Any pointers as to what might have gotten bodged by the Plasma update/upgrade resulting in the loss of display of the graphical desktop environment?
Thanks in advance!
P.S. I had found threads on this forum and on the KDE forum suggesting the exact same problem being caused by having kwin-lowlatency installed and solving by replacing it with stock kwin (5.21), but my machine already is running stock kwin.