[Intel-gfx] [PATCH 3/4] drm/i915: HSW GT3 Slices: exec flag to warn kernel that userspace is using predication

[Chris Wilson]

On Wed, Oct 16, 2013 at 09:12:46AM -0300, Rodrigo Vivi wrote:
> >> +             dev_priv->gt_slices.forcing_full = true;
> >> +             i915_gt_full_immediate(dev, ring);
> >
> > What happens when this fails? If it only partially emits the commands,
> > etc.
> 
> This is a very good question. If it fails, my only concern would be
> the sync between HSW_GT_SLICE_INFO and MI_PREDICATE_RESULT_2. But I
> don't know how to do this during the exec buf without delaying the
> execution. Do you have any suggestion?

Reduce the series of if() to just one, act upon the return value, only
set legacy_userspace_busy to true after making the change. It will
eventually get cleaned up if the dispatch later fails, but we must make
sure that we accurately track hardware state.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre