We have a patch to force NVIDIA to use its own PAT routines rather than trust what the kernel told it under Xen. This was necessary to get the 5xx driver family to function in PV mode under Xen. However, in the 6xx series, NVIDIA removed their own PAT detection routines entirely (as far as I can tell).
We should drop the patch, but we also need to validate that whatever PAT bug it was working around either is fixed in newer kernels + pv + 6xx (or maybe drop PV support for nv kernels).
We have a patch to force NVIDIA to use its own PAT routines rather than trust what the kernel told it under Xen. This was necessary to get the 5xx driver family to function in PV mode under Xen. However, in the 6xx series, NVIDIA removed their own PAT detection routines entirely (as far as I can tell).
We should drop the patch, but we also need to validate that whatever PAT bug it was working around either is fixed in newer kernels + pv + 6xx (or maybe drop PV support for nv kernels).