Memory and I/O resources overlap with 2.6, is that a problem?
Ive been trying to eliminate all the reasons why write combining seems to be disabled for xvideo under 2.6 on my machine (p3-450, bx chipset, tnt video card).
The MTRR seems to be set correct, I dont know about the per page flags but people experiencing simular problems with different devices say they are being set correct, the prefetch memory base seems to be set correctly.
The only major difference I can find between running X under 2.4 and 2.6 is that the X-server shows this in 2.6 :
Screen 0 shares mem & io resources
Also lspci shows an unassigned i/o memory range for the expansion rom under 2.4, but it doesnt under 2.6 (probably because of the overlap).
Anyone know if this could cause the processor to disable uswc/write-combining?