[Intel-gfx] [PATCH 4/4] drm/i915: Don't allocate extra ddb during async flip for DG2

Ville Syrjälä ville.syrjala at linux.intel.com
Mon Jan 24 09:16:36 UTC 2022


On Mon, Jan 24, 2022 at 11:06:53AM +0200, Stanislav Lisovskiy wrote:
> In terms of async flip optimization we don't to allocate
> extra ddb space, so lets skip it.
> 
> v2: - Extracted min ddb async flip check to separate function
>       (Ville Syrjälä)
>     - Used this function to prevent false positive WARN
>       to be triggered(Ville Syrjälä)
> 
> v3: - Renamed dg2_need_min_ddb to need_min_ddb thus making
>       it more universal.
>     - Also used DISPLAY_VER instead of IS_DG2(Ville Syrjälä)
>     - Use rate = 0 instead of just setting extra = 0, thus
>       letting other planes to use extra ddb and avoiding WARN
>       (Ville Syrjälä)
> 
> v4: - Renamed needs_min_ddb as s/needs/use/ to match
>       the wm0 counterpart(Ville Syrjälä)
>     - Added plane->async_flip check to use_min_ddb(now
>       passing plane as a parameter to do that)(Ville Syrjälä)
>     - Account for use_min_ddb also when calculating total data rate
>       (Ville Syrjälä)
> 
> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> ---
>  .../gpu/drm/i915/display/intel_atomic_plane.c |  2 +-
>  .../gpu/drm/i915/display/intel_atomic_plane.h |  3 +-
>  drivers/gpu/drm/i915/intel_pm.c               | 53 ++++++++++++++-----
>  3 files changed, 44 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> index b20cf2c16691..9d79ab987b2e 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> @@ -374,7 +374,7 @@ int intel_plane_atomic_check_with_state(const struct intel_crtc_state *old_crtc_
>  					       old_plane_state, new_plane_state);
>  }
>  
> -static struct intel_plane *
> +struct intel_plane *
>  intel_crtc_get_plane(struct intel_crtc *crtc, enum plane_id plane_id)
>  {
>  	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.h b/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> index ead789709477..aaddcc636f98 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> @@ -23,7 +23,8 @@ unsigned int intel_adjusted_rate(const struct drm_rect *src,
>  				 unsigned int rate);
>  unsigned int intel_plane_pixel_rate(const struct intel_crtc_state *crtc_state,
>  				    const struct intel_plane_state *plane_state);
> -
> +struct intel_plane *intel_crtc_get_plane(struct intel_crtc *crtc,
> +					  enum plane_id plane_id);
>  unsigned int intel_plane_data_rate(const struct intel_crtc_state *crtc_state,
>  				   const struct intel_plane_state *plane_state);
>  void intel_plane_copy_uapi_to_hw_state(struct intel_plane_state *plane_state,
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 8269f1e9c784..fbe6a45801bc 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4988,6 +4988,25 @@ skl_get_total_relative_data_rate(struct intel_atomic_state *state,
>  	return total_data_rate;
>  }
>  
> +static bool use_min_ddb(struct intel_crtc_state *crtc_state,
> +			struct intel_plane *plane)
> +{
> +	struct drm_i915_private *i915 = to_i915(plane->base.dev);
> +
> +	return DISPLAY_VER(i915) >= 13 && crtc_state->uapi.async_flip &&
> +	       plane->async_flip;
> +}
> +
> +static bool use_minimal_wm0_only(const struct intel_crtc_state *crtc_state,
> +				 struct intel_plane *plane)

Please put this function into the right spot to begin with.
Avoids polluting this patch with unrelated code movement.

> +{
> +	struct drm_i915_private *i915 = to_i915(plane->base.dev);
> +
> +	return DISPLAY_VER(i915) >= 13 &&
> +	       crtc_state->uapi.async_flip &&
> +	       plane->async_flip;

Line wrapping is different between the two functions despite the
identical contents, which looks a bit weird.

> +}
> +
>  static u64
>  icl_get_total_relative_data_rate(struct intel_atomic_state *state,
>  				 struct intel_crtc *crtc)
> @@ -5033,8 +5052,15 @@ icl_get_total_relative_data_rate(struct intel_atomic_state *state,
>  		}
>  	}
>  
> -	for_each_plane_id_on_crtc(crtc, plane_id)
> -		total_data_rate += crtc_state->plane_data_rate[plane_id];
> +	for_each_new_intel_plane_in_state(state, plane, plane_state, i) {

for_each_intel_plane_on_crtc() otherwise we miss all
the planes not in the state.

> +		/*
> +		 * We calculate extra ddb based on ratio plane rate/total data rate
> +		 * in case, in some cases we should not allocate extra ddb for the plane,
> +		 * so do not count its data rate, if this is the case.
> +		 */
> +		if (!use_min_ddb(crtc_state, plane))
> +			total_data_rate += crtc_state->plane_data_rate[plane->id];
> +	}
>  
>  	return total_data_rate;
>  }
> @@ -5199,6 +5225,8 @@ skl_allocate_plane_ddb(struct intel_atomic_state *state,
>  	for_each_plane_id_on_crtc(crtc, plane_id) {

for_each_intel_plane_on_crtc()...

>  		const struct skl_plane_wm *wm =
>  			&crtc_state->wm.skl.optimal.planes[plane_id];
> +		struct intel_plane *plane =
> +			intel_crtc_get_plane(crtc, plane_id);

... avoids needing that function.

>  		u64 rate;
>  		u16 extra;
>  
> @@ -5213,9 +5241,14 @@ skl_allocate_plane_ddb(struct intel_atomic_state *state,
>  			break;
>  
>  		rate = crtc_state->plane_data_rate[plane_id];
> +
> +		if (use_min_ddb(crtc_state, plane))
> +			rate = 0;

else
	rate = crtc_state->plane_data_rate[plane_id];

is how I'd write that probably.

> +
>  		extra = min_t(u16, alloc_size,
>  			      DIV64_U64_ROUND_UP(alloc_size * rate,
>  						 total_data_rate));
> +
>  		total[plane_id] = wm->wm[level].min_ddb_alloc + extra;
>  		alloc_size -= extra;
>  		total_data_rate -= rate;
> @@ -5224,13 +5257,19 @@ skl_allocate_plane_ddb(struct intel_atomic_state *state,
>  			break;
>  
>  		rate = crtc_state->uv_plane_data_rate[plane_id];
> +
> +		if (use_min_ddb(crtc_state, plane))
> +			rate = 0;
> +
>  		extra = min_t(u16, alloc_size,
>  			      DIV64_U64_ROUND_UP(alloc_size * rate,
>  						 total_data_rate));
> +
>  		uv_total[plane_id] = wm->uv_wm[level].min_ddb_alloc + extra;
>  		alloc_size -= extra;
>  		total_data_rate -= rate;
>  	}
> +
>  	drm_WARN_ON(&dev_priv->drm, alloc_size != 0 || total_data_rate != 0);
>  
>  	/* Set the actual DDB start/end points for each plane */
> @@ -5497,16 +5536,6 @@ static int skl_wm_max_lines(struct drm_i915_private *dev_priv)
>  		return 31;
>  }
>  
> -static bool use_minimal_wm0_only(const struct intel_crtc_state *crtc_state,
> -				 struct intel_plane *plane)
> -{
> -	struct drm_i915_private *i915 = to_i915(plane->base.dev);
> -
> -	return DISPLAY_VER(i915) >= 13 &&
> -	       crtc_state->uapi.async_flip &&
> -	       plane->async_flip;
> -}
> -
>  static void skl_compute_plane_wm(const struct intel_crtc_state *crtc_state,
>  				 struct intel_plane *plane,
>  				 int level,
> -- 
> 2.24.1.485.gad05a3d8e5

-- 
Ville Syrjälä
Intel


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