[Intel-gfx] [PATCH] drm/i915: Serialize GTT Updates on BXT

[Chris Wilson]

On Mon, May 22, 2017 at 11:07:25AM -0700, Jon Bloomfield wrote:
> BXT requires accesses to the GTT (i.e. PTE updates) to be serialized
> when IOMMU is enabled. This patch guarantees this by wrapping all
> updates in stop_machine and using a flushing read to guarantee that
> the GTT writes have reached their destination before restarting.
> 

Testcase? igt/gem_concurrent_blit shows the failure.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre