Bug 198061 - No MTRR set for the video ram on Radeon XPRESS 200 causing poor performance
No MTRR set for the video ram on Radeon XPRESS 200 causing poor performance
Product: Fedora
Classification: Fedora
Component: xorg-x11-drv-ati (Show other bugs)
x86_64 Linux
medium Severity medium
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Assigned To: X/OpenGL Maintenance List
Depends On:
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Reported: 2006-07-08 18:22 EDT by Henrik Nordstrom
Modified: 2007-11-30 17:11 EST (History)
0 users

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Doc Type: Bug Fix
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Last Closed: 2006-07-22 02:12:37 EDT
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RHEL 7.3 requirements from Atomic Host:
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Description Henrik Nordstrom 2006-07-08 18:22:05 EDT
Description of problem:

No MTRR is set for the video ram, causing very poor performance.

Version-Release number of selected component (if applicable):


How reproducible:


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.
Actual results:

Poor performance

Expected results:

Quite good performance

Additional info:

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
message somewhere..

which leads to
and this for xorg 7

my apologies if the above information is old but it looked promising..
Comment 1 Mike A. Harris 2006-07-22 02:12:37 EDT
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).

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