[Intel-gfx] [PATCH] drm/i915/guc: Restore preempt-context across S3/S4

[Chris Wilson]

Quoting Michał Winiarski (2018-09-20 12:47:07)
> On Wed, Sep 19, 2018 at 09:54:32PM +0100, Chris Wilson wrote:
> > Stolen memory is lost across S4 (hibernate) or S3-RST as it is a portion
> > of ordinary volatile RAM. As we allocate our rings from stolen, this may
> > include the rings used for our preempt context and their breadcrumb
> > instructions. In order to allow preemption following hibernation and
> > loss of stolen memory, we therefore need to repopulate the instructions
> > inside the lost ring upon resume. To handle both module load and resume,
> > we simply defer constructing the ring to first use.
> > 
> > Testcase: igt/drv_selftest/live_gem
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Michał Winiarski <michal.winiarski at intel.com>
> > Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> 
> Reviewed-by: Michał Winiarski <michal.winiarski at intel.com>

And with any luck, I won't be breaking the guc today :)
-Chris