Re: MTRR problem, maybe FB related

[Dave Jones <davej@redhat.com>]

On Fri, Aug 06, 2004 at 07:47:22PM +0200, admin@wodkahexe.de wrote:

 > vesafb: framebuffer at 0xb0000000, mapped to 0xdf80d000, size 6144k
 > vesafb: mode is 1024x768x32, linelength=4096, pages=4

vesafb's mtrr usage is borken. Instead of creating an MTRR the size
of video RAM, it creates one the size of the display.

 > mtrr: 0xb0000000,0x8000000 overlaps existing 0xb0000000,0x400000
 > [drm] Initialized i830 1.3.2 20021108 on minor 0: Intel Corp. 82852/855GM Integrated Graphics Device
 > mtrr: 0xb0000000,0x8000000 overlaps existing 0xb0000000,0x400000
 > [drm] Initialized i830 1.3.2 20021108 on minor 1: Intel Corp. 82852/855GM Integrated Graphics Device (#2)

Then X comes along, sizes the video ram, and tries to create an MTRR
of the correct size, but the framebuffer got there first and bodged it.

I used to see this happening also on my Matrox g550, but it seems
to have 'gone away' in recent times. I haven't checked out why,
but I'm suspecting X now detects this case, and deletes the crap
entry, and puts the proper values in its place.

 > when starting X i'm getting the following in dmesg:
 > 
 > mtrr: base(0xb0020000) is not aligned on a size(0x180000) boundary

This one I can't explain however.

 > mtrr: 0xb0000000,0x8000000 overlaps existing 0xb0000000,0x400000
 > 
 > is there any way to get both working together? (fb + mtrr)

Disable MTRR for vesafb. iirc, there's a boot command line option to do it.

		Dave