adding pat causes conflicting memory types

[justinmattock@gmail.com]

I've seen this for sometime(and reported it a few months back),
but didn't experience any anomalies.
also have seen some(quick google) reports about this(people have been 
unable to boot there systems because of this)

with having pat enabled dmesg shows this:

[   34.699209] [drm] Initialized drm 1.1.0 20060810
[   34.724925] pci 0000:01:00.0: setting latency timer to 64
[   34.725318] [drm] Initialized radeon 1.29.0 20080528 on minor 0
[   35.192313] [drm] Setting GART location based on new memory map
[   35.193444] [drm] Loading R500 Microcode
[   35.193513] [drm] Num pipes: 1
[   35.193529] [drm] writeback test succeeded in 1 usecs
[   35.541595] X:1837 conflicting memory types 40000000-48000000 
write-combining<->uncached-minus
[   35.541602] reserve_memtype failed 0x40000000-0x48000000, track 
write-combining, req write-combining
[   36.081888] X:1837 conflicting memory types 40000000-48000000 
write-combining<->uncached-minus
[   36.081895] reserve_memtype failed 0x40000000-0x48000000, track 
write-combining, req write-combining


when disabling pat I get no message just this:

[   34.649170] Linux agpgart interface v0.103
[   34.699209] [drm] Initialized drm 1.1.0 20060810
[   34.724925] pci 0000:01:00.0: setting latency timer to 64
[   34.725318] [drm] Initialized radeon 1.29.0 20080528 on minor 0
[   35.192313] [drm] Setting GART location based on new memory map
[   35.193444] [drm] Loading R500 Microcode
[   35.193513] [drm] Num pipes: 1
[   35.193529] [drm] writeback test succeeded in 1 usecs


FWIW: with a macbook there is no inconvenience, but I guess that changes
with others.

-- Justin P. Mattock