[Intel-gfx] [PATCH i-g-t] tests/gem_mmap_gtt(huge_bo): Use pread more to verify domain transfer.

[Joonas Lahtinen]

On ke, 2015-05-06 at 14:15 +0100, Chris Wilson wrote:
> On Wed, May 06, 2015 at 03:31:10PM +0300, Joonas Lahtinen wrote:
> > 
> > Use pread right after moving out of CPU domain to verify all
> > writes flushed correctly.
> 
> Wrong test, see gem_pread. Adding extra work may have the unintended
> side-effects of masking bugs. If you want to mix access modes, call it a
> new test, and that is handled by gem_concurrent_blt (which once again is
> difting far beyond the original name).

This is specifically for the huge_bo test, where the kernel side
handling is expected to be different than for the others, so it stresses
the code path related to huge BO's.

Better wording to add to it:
"Make sure that the introduction of the partial GTT mappings which are
expected to be in use when mapping an object bigger than the aperture
size do not corrupt the contents of the backing storage"

Regards, Joonas

> -Chris
>