Poor compositing performance on 965Q chipset with intel 2.2.1 driver

Simon Farnsworth simon.farnsworth at onelan.co.uk
Fri May 9 07:14:22 PDT 2008

Barry Scott wrote:
> Bill Crawford wrote:
>> 2008/5/9 Barry Scott <barry.scott at onelan.co.uk>:
>>>  # cat /proc/mtrr
>>>  reg00: base=0x00000000 (   0MB), size= 256MB: write-back, count=1
>>>  reg01: base=0x10000000 ( 256MB), size= 128MB: write-back, count=1
>>>  reg02: base=0x18000000 ( 384MB), size=  64MB: write-back, count=1
>>>  reg03: base=0x1c000000 ( 448MB), size=  32MB: write-back, count=1
>>>  reg04: base=0x1e000000 ( 480MB), size=  16MB: write-back, count=1
>>>  reg05: base=0x1f000000 ( 496MB), size=   8MB: write-back, count=1
>>>  reg06: base=0xe0000000 (3584MB), size= 256MB: write-combining, count=1
On another 965Q that exhibits the problem, we get:

# cat /proc/mtrr
reg00: base=0x00000000 (   0MB), size= 512MB: write-back, count=1
reg01: base=0x1f000000 ( 496MB), size=  16MB: uncachable, count=1
reg02: base=0xe0000000 (3584MB), size= 256MB: write-combining, count=1

>> That looks suspiciously like the "fan controller" related BIOS bug
>> that turned up not long ago. Can't remember if it made it into
>> bugzilla, but it was fixed by a bios upgrade ...
>> Suggest looking in BIOS options for something to do with a fan and
>> turning it off.
Assuming you're thinking of 
http://lists.freedesktop.org/archives/xorg/2007-June/025105.html, we 
don't have the necessary options in the BIOS, but some of our boxes that 
demonstrate poor performance don't have the same block of bad-looking MTRRs.
Any more ideas?

Simon Farnsworth

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