[Intel-gfx] [PATCH v2] drm/i915/vlv: Enabling the TLB invalidate bit in GFX Mode register

[Gupta, Sourab]

On Fri, 2014-03-21 at 16:52 +0000, Chris Wilson wrote:
> On Fri, Mar 21, 2014 at 08:58:08PM +0530, sourab.gupta at intel.com wrote:
> > From: Akash Goel <akash.goel at intel.com>
> > 
> > This patch Enables the bit for TLB invalidate in GFX Mode register.
> > 
> > According to bspec,  When enabled this bit limits the invalidation
> > of the TLB only to batch buffer boundaries, to pipe_control
> > commands which have the TLB invalidation bit set and sync flushes.
> > If disabled, the TLB caches are flushed for every full flush of
> > the pipeline.
> > 
> > v2: Explicitly enabling TLB invalidate bit instead of assuming
> > default 1 (Chris Wilson)
> 
> Right, but there is nothing special about this code for vlv, all of gen7
> share the same TLB invalidation code, and there is no documented reason
> not to do the switch. So do a cursory test on ivb/hsw and send a patch
> that doesn't say FIXME.
> -Chris
> 
Hi Chris,
I agree, this could be applicable to ivb also. But we are constrained by
the availability of ivb/hsw machines and we're not able to test it on
those. We didn't want to cause any regression on those platforms. Thats
why we were limiting our patch to vlv only with a FIXME comment. We've
done this for other WAs also.

If required we can put this patch for full GEN7 (not tested on ivb/hsw)
and keep our fingers crossed! :)

Regards,
Sourab