[Intel-gfx] [PATCH] drm/i915: Reserve powerctx for chv from the stolen allocator

[Chris Wilson]

Quoting Ville Syrjälä (2017-11-06 14:43:12)
> On Mon, Nov 06, 2017 at 02:32:50PM +0000, Chris Wilson wrote:
> > Quoting Ville Syrjälä (2017-11-06 14:23:24)
> > > On Sat, Nov 04, 2017 at 09:43:38PM +0000, Chris Wilson wrote:
> > > > Ensure that we do not overwrite the cherryview power context by
> > > > reserving its range in the stolen allocator; exactly like how we handle
> > > > the same reservation for valleyview.
> > > 
> > > IIRC CHV pctx must live inside the "reserved" region. So this
> > > should never happen.
> > 
> > It's supposed to. Otoh, the duplication for no good reason is inane.
> 
> Well, it's not really duplication because it allocates the object in a
> different place. VLV wants it below the reserved region, CHV wants it
> inside the reserved region. Given that the reserved region isn't part of
> the mm we can't use the VLV code to allocate the pctx correctly for CHV.

There's no reason why we can't allow the preallocations to be inside the
reserved portion while preventing allocations from it, it's just a
matter of tracking. It's just so aggravating to have multiple drivers
making independent decisions on shared resources.
-Chris