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

[Andrzej Hajda <andrzej.hajda@intel.com>]

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.

Regards
Andrzej

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