Red Hat Bugzilla – Bug 198061
No MTRR set for the video ram on Radeon XPRESS 200 causing poor performance
Last modified: 2007-11-30 17:11:36 EST
Description of problem:
No MTRR is set for the video ram, causing very poor performance.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Start X
2. Try some graphics intensive app. Poor performance
3. cat /proc/mtrr, no MTRR seen for the video memory region.
Quite good performance
A workaround is to create the MTRR manually. The following works on my box, but
it's quite hardware dependent and the numbers need to be collected for the
specific hardware (lspci -v and xorg logs is good sources)..
echo "base=0xf8000000 size=0x4000000 type=write-combining" > /proc/mtrr
Found the following possibly relevant changeset which was linked from a related
which leads to
and this for xorg 7
my apologies if the above information is old but it looked promising..
Try xorg-x11-server-Xorg-1.1.1 or newer in rawhide, which was released since
the above upstream bug was commented on being resolved. (IOW, the fix should
be in Xorg 7.1).