Re: [PATCH 1/2] drm/i915: Simplify flush_cpu_write_domain

Ville Syrjälä
2015-01-21T14:25:43Z

On Wed, Jan 21, 2015 at 03:13:58PM +0100, Daniel Vetter wrote:
> On Wed, Jan 21, 2015 at 3:08 PM, Ville Syrjälä
> <ville.syrjala@linux.intel.com> wrote:
> >> @@ -3735,7 +3733,7 @@ i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj, bool write)
> >> if (ret)
> >> return ret;
> >>
> >> - i915_gem_object_flush_cpu_write_domain(obj, false);
> >> + i915_gem_object_flush_cpu_write_domain(obj);
> >
> > This is the only place where there's a slight change in behaviour.
> > Previosuly we would not clflush here when pin_display==true, but from
> > now on we will. I had a patch to do only this change (part of some FBC
> > series), but IIRC you argued it could hide bugs. I guess you've
> > now changed you mind ;)
>
> Hm, I don't remember that I've shot down a patch to change this and I
> can't come up with any reason any more why. But you're right that the
> commit message is a bit too silent about the behavioral change here.
> Lazy me will try harder and augment it when merging.

http://lists.freedesktop.org/archives/intel-gfx/2013-November/036421.html

Also seems Chris already suggested dropping the force parameter back
then, but no one took the bait:
http://lists.freedesktop.org/archives/intel-gfx/2013-November/036346.html

--
Ville Syrjälä
Intel OTC