I just rechecked the problem; Ctrl-Alt-F1 still just changed somepixel colours but Ctrl-Alt-F7 this time seems to have crashed something (Gnome session?), putting me back to the login screen. Afterwards I found that Ctrl-Alt-F7 had the same effect as Ctrl-Alt-F1..6, namely recolouring parts of the screen and freezing it. Instead, Ctrl-Alt-F8 had the effect of putting me back to my running X/Gnome session.
I checked this many times as I found it hard to believe. Ctrl-Alt-F7 had joined the behaviour of Ctrl-Alt-F1..6 (freezing), and Ctrl-Alt-F8 had taken over the function of Ctrl-Alt-F7 (restoring the graphical session). Or, you might say, Ctrl-Alt-F7 and Ctrl-Alt-F8 had swapped functions.
After restarting the system everything now is as usual (Ctrl-Alt-F[1234568]) freeze the screen, Ctrl-Alt-F7 unfreezes it).
No idea if this could be a hint about what's going wrong but it looks like we have no real clues, so I thought I'd better report anything unusual.
I just rechecked the problem; Ctrl-Alt-F1 still just changed somepixel colours but Ctrl-Alt-F7 this time seems to have crashed something (Gnome session?), putting me back to the login screen. Afterwards I found that Ctrl-Alt-F7 had the same effect as Ctrl-Alt-F1..6, namely recolouring parts of the screen and freezing it. Instead, Ctrl-Alt-F8 had the effect of putting me back to my running X/Gnome session.
I checked this many times as I found it hard to believe. Ctrl-Alt-F7 had joined the behaviour of Ctrl-Alt-F1..6 (freezing), and Ctrl-Alt-F8 had taken over the function of Ctrl-Alt-F7 (restoring the graphical session). Or, you might say, Ctrl-Alt-F7 and Ctrl-Alt-F8 had swapped functions.
After restarting the system everything now is as usual (Ctrl-Alt- F[1234568] ) freeze the screen, Ctrl-Alt-F7 unfreezes it).
No idea if this could be a hint about what's going wrong but it looks like we have no real clues, so I thought I'd better report anything unusual.