[Intel-gfx] [PATCH 1/2] drm/i915/guc: fix GuC suspend/resume

[Chris Wilson]

Quoting Daniele Ceraolo Spurio (2018-10-15 23:10:08)
> The ENTER/EXIT_S_STATE actions queue the save/restore operation in GuC
> FW and then return, so waiting on the H2H is not enough to guarantee
> GuC is done.
> When all the processing is done, GuC writes 0 to scratch register 14,
> so we can poll on that. Note that GuC does not ensure that the value
> in the register is different from 0 while the action is in progress
> so we need to take care of that ourselves as well.
> 
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>

Explains itself very well,
Acked-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris