Hi All,

With 2.6.29.1 (stock kernel), on my Dell Inspiron 1545, X freezes for
15-20 seconds at a time randomly every 10 seconds or so making it
unusable. Currently, I use the 2.6.29.1-54.fc11.x86_64 kernel that comes
with Fedora 11 Beta which has the same problem but only when X is left
idle for a period of time. The kernel log is overrun by messages of the
type:

X:2802 freeing invalid memtype e4b42000-e4b43000
X:2802 freeing invalid memtype e4b43000-e4b44000
X:2802 freeing invalid memtype e4b44000-e4b45000

This I believe is related to this:

mtrr: type mismatch for e0000000,10000000 old: write-back new:
write-combining
[drm] MTRR allocation failed.  Graphics performance may suffer.

The MTRR setup is below:
reg00: base=0x000000000 (    0MB), size=32768MB, count=1: write-back
reg01: base=0x0e0000000 ( 3584MB), size=  512MB, count=1: uncachable
reg02: base=0x07dc00000 ( 2012MB), size=    4MB, count=1: uncachable
reg03: base=0x07e000000 ( 2016MB), size=   32MB, count=1: uncachable

I think the first entry is bogus. Both kernels come with the
MTRR sanitize option enabled but the code is unable to find an
optimal value. Is there any way to correct this? What values for
mtrr_gran_size and mtrr_chunk_size would be appropriate?

While the stock kernel is not usable, the Fedora kernel is okay and X
performance is not slow as well (500fps with glxgears). I've attached
the dmesg log from the Fedora kernel (stock kernel buffer is overrun
in a few seconds) and the configs of both. Let me know if you need
anything else.

Regards,
David.