broken login screen to KDM after KDE SC 4.4 upgrade

[dmatt]

Binary package hint: kdebase-workspace

After upgrade to KDE 4.4.0 (from KDE 4.3.5) in Kubuntu 9.10, screen goes blank
just before kdm login screen (sometimes it is possible to see login screen for
short moment). It is possible to move with mouse cursor, but it is huge. I
guess screen resolution is down to something like 640x480. Attempting to switch
to ttys show color patterns and system appears to be frozen. It is possible to
reboot with ALT+SYSRQ+B.

After discussion with others affected on #Kubuntu channel on freenode we found following
workarounds:
- immediate restart of KDM with ALT+E, afterwards it works
- switching to other tty and back to tty7
- using GDM or other login manager instead of KDM
- boot to recovery console and start KDM manually

Things which did not help:
- reinstalling KDM, kubuntu-desktop, xorg-driver-fglrx
- removing/renaming .kde folder

All available updates are applied. After successful login using any of the workarounds ttys remain unusable filled with graphical color stripes garbage.
This problem was originally reported as https://bugs.kde.org/show_bug.cgi?id=226392 and following on J. Ridell advice I am opening it here. It is obviously not resolved by simple restarting.

[tmokeefe (timothy-okeefe)]

Same issue. Only minor difference is that I do see the new KDE 4.4 login screen, however when I enter my password and hit enter I get the same black screen with giant mouse pointer.

Switch to virtual console shows colored lines. Switching back to virtual console F7 actually shows the desktop and everything appears to function normally.

Dell Studio XPS 16
Kubuntu 9.10 (64-bit)
ATI Catalyst 10.1 (fglrx)

[tmokeefe (timothy-okeefe)]

No matter what, whenever I switch to a virtual console it shows the multicolored lines. Completely unusable. Doesn't matter if I flip to F4, F7, F4, F3, F7, F3.

[Duskao (hjcaton)]

Similar for me, but I tried it with fglrx and later with the open source Radoen drivers. I got to the CLI and logged in that way and tried to start plasma-desktop, but got an error saying X11 was not installed. I tried reinstalling X11. Didn't work. I did not get a giant pointer or any kdm.

Kubuntu 9.10 64-bit
ATI Catalyst 10.1 (also tried with xorg-Radeon)
Radeon HD4850