[Libdlo] udlfb rotation performance issue

Alexander Todorov atodorov at otb.bg
Tue Sep 20 08:15:07 PDT 2011

Hi folks,
I'm having very bad experience using rotation in udlfb.

I enabled fb_defio=1 in modprobe.conf

When not rotating the image looks nice, not major slowness observed. Everything 
seems to work just fine. No picture artefacts observed.

When specifying Option "Rotate" "CW" or "CCW" in xorg.conf the picture is 
rotated accordingly but there's very slow response.

When the system boots up (in a multiseat config) I still see the green screen. 
If I move the mouse parts of the login screen start to appear. As if the picture 
is refreshed only around the mouse pointer area.

While moving the mouse Xorg consumes around 10% of CPU according to top.

I have one of the latest drivers. Compiled as a module for a 
2.6.32-131.12.1.el6.i686 kernel. Sources are taken from 
kernel-3.1.0-0.rc6.git0.4.fc16.src.rpm from Fedora 

Xorg is 1.7.7

fbdev driver with damage support is version 0.4.2 taken from git.plugable.com 
long time ago.

Has anyone seen such behaviour? What can I do to debug the performance issue and 
possibly fix it?


More information about the Libdlo mailing list