[Intel-gfx] [PATCH 2/3] drm/i915: Fix MOCS PTE setting for gen9+

[Ville Syrjälä]

On Tue, Oct 13, 2020 at 04:51:00PM +0100, Chris Wilson wrote:
> Quoting Ville Syrjala (2020-10-07 13:03:28)
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > Fix up the MOCS PTE setting to really get the LLC cacheability
> > from the PTE rather than hardocoding it to LLC or LLC+eLLC.
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/gt/intel_mocs.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/gt/intel_mocs.c b/drivers/gpu/drm/i915/gt/intel_mocs.c
> > index 632e08a4592b..6f771a482608 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_mocs.c
> > +++ b/drivers/gpu/drm/i915/gt/intel_mocs.c
> > @@ -124,7 +124,7 @@ struct drm_i915_mocs_table {
> >                    LE_1_UC | LE_TC_2_LLC_ELLC, \
> >                    L3_1_UC), \
> >         MOCS_ENTRY(I915_MOCS_PTE, \
> > -                  LE_0_PAGETABLE | LE_TC_2_LLC_ELLC | LE_LRUM(3), \
> > +                  LE_0_PAGETABLE | LE_TC_0_PAGETABLE | LE_LRUM(3), \
> >                    L3_3_WB)
> >  
> >  static const struct drm_i915_mocs_entry skl_mocs_table[] = {
> > @@ -274,7 +274,7 @@ static const struct drm_i915_mocs_entry icl_mocs_table[] = {
> >                    L3_1_UC),
> >         /* Base - L3 + LeCC:PAT (Deprecated) */
> >         MOCS_ENTRY(I915_MOCS_PTE,
> > -                  LE_0_PAGETABLE | LE_TC_1_LLC,
> > +                  LE_0_PAGETABLE | LE_TC_0_PAGETABLE,
> >                    L3_3_WB),
> 
> Makes sense. Did the PAGETABLE bit carry forward into tgl? That might
> fixup the new regression...

At least I still see it in the docs. What troubles me here is the
"deprecated" comment someone added. If this is deprecated how are we
supposed to configure cachine for display surfaces?

> 
> For the two given here, it certainly exists and makes a whole lot of
> sense,
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> -Chris

-- 
Ville Syrjälä
Intel