Bug#636135: Also affected
I'm also affected by this, after I switched to radeon (from fglrx). I'm
using a Mobility Radeon HD 5650. This seems to happen regardless of the
display port I'm using (VGA or HDMI) and of the screen. radeon is
working pretty well otherwise. I'm using Linux 3.0 on i386 with the
In fact, I switched a month ago and hadn't noticed this problem until
recently. This does not always happen when just "logging out of KDE", it
happens when kdm resets X. That means this won't happen if you directly
halt the PC from KDE. This also won't happen if you start a second
session and use "Logout" from that session (as you'll be switched to the
X server of the first session). I think the only case where this happens
is if you have a single session open and close it without halting the
PC. This must be a relatively rare scenario. One reason to do it would
be to restart X or KDE without rebooting. Another case could be a user
on a multi-user machine who's done and decides to logout so that his
session won't consume memory when another user opens his session.
I tried the workaround and it worked. I just had to uncomment
#TerminateServer=true in /etc/kde4/kdm/kdmrc (on line 513).
I can also confirm that blacklisting radeon solved... and oddly enough,
that solution persists after removing radeon from the blacklist. I don't
know how that can be. The only thing I see is that I played with desktop
effects. Just after removing radeon from the blacklist, the black screen
still wouldn't show, even though radeon was loaded, but I also wouldn't
get desktop effects anymore. So I played with desktop effects a bit
trying to get them back, and that eventually worked. I am now back to my
original situation (radeon X driver with the radeon LKM loaded and
firmware installed, KDE effects enabled), the only apparent thing
changed is that I can logout of KDE without issues...
Also, the last time I saw the problem, I realized the same as oz
reported, that is kdm is still working, it's just showing nothing. I was
even able to login. Unfortunately, that didn't solve the problem. Xorg
got to 100% CPU and I eventually restarted.
I looked for errors and there are sure a lot, but the only very
suspicious chunk I found was:
klauncher(28046) kdemain: No DBUS session-bus found. Check if you have
started the DBUS server.
kdeinit4: Communication error with launcher. Exiting!
kdmgreet(28038)/kdecore (K*TimeZone*): KSystemTimeZones: ktimezoned
initialize() D-Bus call failed: "Not connected to D-Bus server"
I still wonder what this is about.