[Intel-gfx] [PATCH] drm/i915/cnl: Use mmio access to context status buffer

[Chris Wilson]

Quoting Mika Kuoppala (2018-04-12 15:58:02)
> Evidence indicates that Cannonlake HWSP is not coherent
> as it should. Revert to using mmio access for now.
> 
> Testcase: igt/gem_ctx_switch
> References: https://bugs.freedesktop.org/show_bug.cgi?id=105888
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Rafael Antognolli <rafael.antognolli at intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Signed-off-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>

Acked-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris