On April 22, 2009, Robert Noland wrote: > On Wed, 2009-04-22 at 17:39 -0700, Norbert Papke wrote: > > 0x0/0x100000000 BIOS write-back set-by-firmware active > > 0x100000000/0x40000000 BIOS write-back set-by-firmware active > > 0xc0000000/0x40000000 BIOS uncacheable set-by-firmware active > > MTRR is failing in many cases... It seems that your BIOS is doing what > both of my newer machines are doing and setting a global range to > write-back. I'm also guessing that 0xc0000000 is your framebuffer.
Correct. The framebuffer starts at 0xd0000000, still covered by that last range. > We > aren't allowed to overlap either of these ranges with a write combined > region according to the specs. We would have to handle > splitting/merging regions which we don't currently do. I looked at this > just the other day, but it is reasonably complex to make that work right > and accommodate all of the merging/splitting of regions. > > We are allowed to use PAT on either of these types of regions to enable > write-combining. The drm code already does this for some allocations > that are not mapped to user space. The problem with PAT is that all > mappings of a given region need to have the same type and we don't > currently have any way to specify that for user space mappings. This is > fwiw, the last of Nvidia's feature requests as well. I've started > looking at it, but I have a lot of learning to do on the vm system > still. Thanks for taking the time to explain. Your posts are always very informative. I am learning quite a lot about the complexities involved. There is yet another thing I don't understand. With other graphics cards, including my G45 internal graphics adaptor, the /dev/agpgart device is created. I don't see this device with the Radeon card. Is this expected because it is not needed for PCIe? Cheers, -- Norbert Papke. npa...@acm.org _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
