Version: (using KDE 4.4.1) Compiler: GCC 4.4.3 Target: x86_64-unknown-linux-gnu Configured with: ../gcc-4.4.3/configure --prefix=/usr --libexecdir=/usr/lib --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --enable-languages=c,c++,fortran --disable-multilib --disable-bootstrap OS: Linux Installed from: Compiled From Sources I suffer of strange painting artifacts on opened windows of several applications (see the screenshot). Most frequently it appears when switching to window using Alt+Tab. Seems that some areas of window aren't redrawn. If to scroll down and then up, everything become ok. Looks VERY similar to bug #187356 (please duplicate it if it's so). But in my case Xserver version is 1.7.x (I've tried 1.7.1 to 1.7.5, no changes) and Qt 4.6.2.
Created attachment 41453 [details] Screenshot of the problem
I doubt this is a KDE problem, as this looks more like a problem with the graphics drivers, but KWin developers may know a solution.
I think it is a driver bug, too. But to be sure: from your screenshot it looks like you do not use desktop effects? What is your graphics driver?
It's radeonhd-1.3.0 now. I also tried different versions of xf86-video-ati (6.12.x branch) with the same effect. According to bug #187356 it could be something with Xserver, but they reported it was fixed in 1.6.2. Maybe there is regression in 1.7.x branch (can't try 1.6.x branch cause I need to rebuild whole X for it, but if we need it it's possible).
and you are using desktop effects?
No, there's no OpenGL support for my card so it's impossible to enable them (check drops on clicking Apply).
In that case really a driver issue as kwin does not handle window painting if compositing is disabled. Sorry
Ok. Could you suggest, it's exactly driver problem or could be another part of X (maybe, Xserver)?
My fair guess is, that it is a driver issue. As you mentioned it does not support OpenGL, so we have to consider that driver as unfinished ;-) But as I do neither have your graphics card, nor your system I can only guess.
Thank you, Martin. Will try to fix it)
as and _iff_ you don't use compositing at all, you should first extend /etc/X11/xorg.conf by Section "Extensions" Option "Composite" "Disable" EndSection in case that doesn't help, add Option "XaaNoOffscreenPixmaps" "true" tothe Screen section (this is not exactly a performance push, so disable it on no success) and while i've no idea whether the driver supports it at all, you probably want Option "BackingStore" "True" in the device section w/o compositing
Thomas, thanks for your advice, I've added everything you've mentioned and bug luckily seems to go away. But performance is just horrible. You've written it could be because of XaaNoOffscreenPixmaps option, will try to switch it off. But anyway, we know, it's definitely a driver problem. Thank you.