It appears that the i915 family driver used to insert the mtrr in older kernels and returns in the latest drivers in the 2.6.30-rc series. It appears that the current driver only inserts the mtrr when GEM is being used. Had a go at backporting the fix for this from upstream. I have built kernels with this patch, and they seem to work on my Intel based laptop:
$ cat /proc/mtrr reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back reg01: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back reg02: base=0x100000000 ( 4096MB), size= 1024MB, count=1: write-back reg03: base=0x0be000000 ( 3040MB), size= 32MB, count=1: uncachable reg04: base=0x0ffe00000 ( 4094MB), size= 2MB, count=1: write-protect reg05: base=0x0bde00000 ( 3038MB), size= 2MB, count=1: uncachable reg06: base=0x0d0000000 ( 3328MB), size= 256MB, count=1: write-combining If those of you who are affected by this could test out the Jaunty kernels below and report back here that would be very helpful. In particular could you report the output of 'cat /proc/mtrr' with the new kernel. Kernels are at the URL below: http://people.ubuntu.com/~apw/lp314928-jaunty/ -- [i915GM] MTRR entry gets removed when restarting xorg - causes corruption on ttys https://bugs.launchpad.net/bugs/314928 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs