[Intel-gfx] [PATCH 4/4] i915: fix remap_io_sg to verify the pgprot

[Christoph Hellwig]

On Sun, May 09, 2021 at 03:33:29AM +0800, youling257 wrote:
> This patch cause "x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x064a2000-0x064a2fff], got write-back" problem.
> my 2GB ram Bay trail z3735f tablet runing on android-x86, "i915: fix remap_io_sg to verify the pgprot" cause this problem.

So this is the memtype verification added by the patch, meaning that the
old code did in fact not call into track_pfn_remap with the right flags.

Can the i915 maintainers take a look at making sure the page permissions
here make sense?