[Intel-gfx] [PATCH] drm/i915: Return IDI Hash Mask setup for gen9+

[Rodrigo Vivi]

On Thu, Sep 14, 2017 at 07:25:11PM +0000, Chris Wilson wrote:
> Quoting Rodrigo Vivi (2017-09-14 20:18:41)
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index f445587c1a4b..25b59dbb29b0 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -4714,7 +4714,7 @@ int i915_gem_init_hw(struct drm_i915_private *dev_priv)
> >         /* Double layer security blanket, see i915_gem_init() */
> >         intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
> >  
> > -       if (HAS_EDRAM(dev_priv) && INTEL_GEN(dev_priv) < 9)
> > +       if (HAS_EDRAM(dev_priv))
> >                 I915_WRITE(HSW_IDICR, I915_READ(HSW_IDICR) | IDIHASHMSK(0xf));
> 
> > "It is required for GFX Driver to set [19:16] to 1 when
> > eDRAM configuration is enabled."
> 
> 0xf != 1 ?

yeap... I had same question here...
but the old behaviour check against the old spec convinced my brain that
"[19:16] = 1" means "[19]=1 & [18]=1 & [17]=1 & [16]=1"

otherise they would just tell [16]=1 or  [IDI HASH MASK]=1 or [21:16]=1

but that really seems a big elephant that needs more clarification as Ville
mentioned...

> -Chris