On Thu, Sep 14, 2017 at 07:44:29PM +0000, Ville Syrjälä wrote:
> On Thu, Sep 14, 2017 at 12:18:41PM -0700, Rodrigo Vivi wrote:
> > Spec teels:
> > "It is required for GFX Driver to set [19:16] to 1 when
> > eDRAM configuration is enabled."
> >
> > This basically reverts commit 666fbcf5c21d ("drm/i915: Don't
> > program eLLC IDI hash mask for gen9+")
> >
> > This requirement hasn't changed since HSW up to CNL.
> > But that commit was created before EDRAM was properly
> > organized with commit 3accaf7e734d ("drm/i915: Store
> > and use edram capabilities")
> >
> > Cc: Mika Kuoppala <[email protected]>
> > Cc: Matthew Auld <[email protected]>
> > Cc: Chris Wilson <[email protected]>
> > Signed-off-by: Rodrigo Vivi <[email protected]>
> > ---
> > drivers/gpu/drm/i915/i915_gem.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > 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));
>
> Hmm. For me the spec seems to be saying
> "Note: It is required for GFX Driver to set [19:16] to 1 when eDRAM
> configuration is enabled.
> For Skylake, S/W is not needed to program this register as eDRAM is a
> memory side cache."
Oh I had missed the SKL specoific version... was looking to an older and a
newer...
>
> But for CNL I only see the first sentence. Does that mean they moved
> the eLLC back to the ring side of the system agent, or just someone
> forgot to update this for CNL? The fact that eLLC moved to the memory
> side of the system agent on SKL isn't really mentioned anywhere else
> in the spec either AFAICS. Seems like a rather big elephant to overlook.
> Might be nice to get some clarification into the spec for this stuff.
>
> Oh and I wonder what we should be doing with bits [21:20]?
good question...
also if it is whole 0xf or only 1 to the whole field.
>
> >
> > if (IS_HASWELL(dev_priv))
> > --
> > 2.13.5
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > [email protected]
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Ville Syrjälä
> Intel OTC
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