Comment 64 for bug 314928

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/