Re: [PATCH v2 09/15] drm/i915: Fix MTL initial plane readout

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Dec 19, 2023 at 11:58:36AM +0100, Andrzej Hajda wrote:
> On 15.12.2023 11:59, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > 
> > MTL stolen memory looks more like local memory, so use the
> > (now fixed) lmem path when doing the initial plane readout.
> > 
> > Cc: Paz Zcharya <pazz@chromium.org>
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >   .../drm/i915/display/intel_plane_initial.c    | 25 +++++++++++++------
> >   1 file changed, 18 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_plane_initial.c b/drivers/gpu/drm/i915/display/intel_plane_initial.c
> > index db594ccf0323..c72d4cacf631 100644
> > --- a/drivers/gpu/drm/i915/display/intel_plane_initial.c
> > +++ b/drivers/gpu/drm/i915/display/intel_plane_initial.c
> > @@ -59,7 +59,7 @@ initial_plane_vma(struct drm_i915_private *i915,
> >   		return NULL;
> >   
> >   	base = round_down(plane_config->base, I915_GTT_MIN_ALIGNMENT);
> > -	if (IS_DGFX(i915)) {
> > +	if (IS_DGFX(i915) || HAS_LMEMBAR_SMEM_STOLEN(i915)) {
> >   		gen8_pte_t __iomem *gte = to_gt(i915)->ggtt->gsm;
> >   		gen8_pte_t pte;
> >   
> > @@ -73,11 +73,20 @@ initial_plane_vma(struct drm_i915_private *i915,
> >   		}
> >   
> >   		phys_base = pte & GEN12_GGTT_PTE_ADDR_MASK;
> > -		mem = i915->mm.regions[INTEL_REGION_LMEM_0];
> > +
> > +		if (IS_DGFX(i915))
> > +			mem = i915->mm.regions[INTEL_REGION_LMEM_0];
> > +		else
> > +			mem = i915->mm.stolen_region;
> > +		if (!mem) {
> > +			drm_dbg_kms(&i915->drm,
> > +				    "Initial plane memory region not initialized\n");
> > +			return NULL;
> > +		}
> >   
> >   		/*
> > -		 * We don't currently expect this to ever be placed in the
> > -		 * stolen portion.
> > +		 * On lmem we don't currently expect this to
> > +		 * ever be placed in the stolen portion.
> >   		 */
> >   		if (phys_base < mem->region.start || phys_base > mem->region.end) {
> >   			drm_err(&i915->drm,
> > @@ -94,11 +103,13 @@ initial_plane_vma(struct drm_i915_private *i915,
> >   	} else {
> >   		phys_base = base;
> >   		mem = i915->mm.stolen_region;
> > +		if (!mem) {
> > +			drm_dbg_kms(&i915->drm,
> > +				    "Initial plane memory region not initialized\n");
> > +			return NULL;
> > +		}
> 
> Code duplication suggests, we could try to move this out ifs.
> The extra check should be harmless in case of 1:1.

With the lmem vs. smem split later this is needed in both branches.
Maybe we can re-unify it later if/when we add the PTE redout for the
smem case.

> 
> Regards
> Andrzej
> 
> >   	}
> >   
> > -	if (!mem)
> > -		return NULL;
> > -
> >   	size = round_up(plane_config->base + plane_config->size,
> >   			mem->min_page_size);
> >   	size -= base;

-- 
Ville Syrjälä
Intel