I have a GTX 460 using the 310.19 driver.
I'm trying to use it without PAT support. I'm loading the nvidia kernel module driver with NVreg_UsePageAttributeTable=0
From the kernel messages I can see:
[ 94.534963] NVRM: loading NVIDIA UNIX x86_64 Kernel Module 310.19 Thu Nov 8 00:52:03 PST 2012
[ 94.535125] NVRM: builtin PAT support disabled, falling back to MTRRs.
[ 126.927848] NVRM: GPU at 0000:01:00: GPU-2d2df840-6445-2af1-fc01-00f7c8346757
However, it doesn't seem to be using MTRR, at least I do not see any new MTRR entries in /proc/mtrr after the driver is loaded or after X has started. (I'm expecting to see some new write-combining MTRR region created)
And without PAT and MTRR, 3D performance is dreadful (3-4fps)
Is there something that can be done here?