Re: [Intel-gfx] [PATCH 1/8] drm/i915: Extract intel_crtc_ddb_weight()

["Lisovskiy, Stanislav" <stanislav.lisovskiy@intel.com>]

On Tue, Oct 27, 2020 at 10:39:48PM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> skl_ddb_get_pipe_allocation_limits() doesn't care how the weights
> for distributing the ddb are caclculated for each pipe. Put that
> calculation into a separate function so that such mundane details
> are hidden from view.
> 
> Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

> ---
>  drivers/gpu/drm/i915/intel_pm.c | 46 ++++++++++++++++++++-------------
>  1 file changed, 28 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 0ef01a01ef8d..d14cdedc4ac3 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4084,6 +4084,25 @@ u32 skl_ddb_dbuf_slice_mask(struct drm_i915_private *dev_priv,
>  	return slice_mask;
>  }
>  
> +static unsigned int intel_crtc_ddb_weight(const struct intel_crtc_state *crtc_state)
> +{
> +	const struct drm_display_mode *adjusted_mode =
> +		&crtc_state->hw.adjusted_mode;
> +	int hdisplay, vdisplay;
> +
> +	if (!crtc_state->hw.active)
> +		return 0;
> +
> +	/*
> +	 * Watermark/ddb requirement highly depends upon width of the
> +	 * framebuffer, So instead of allocating DDB equally among pipes
> +	 * distribute DDB based on resolution/width of the display.
> +	 */
> +	drm_mode_get_hv_timing(adjusted_mode, &hdisplay, &vdisplay);
> +
> +	return hdisplay;
> +}
> +
>  static u8 skl_compute_dbuf_slices(const struct intel_crtc_state *crtc_state,
>  				  u8 active_pipes);
>  
> @@ -4098,7 +4117,7 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
>  	struct intel_atomic_state *intel_state = to_intel_atomic_state(state);
>  	struct drm_crtc *for_crtc = crtc_state->uapi.crtc;
>  	const struct intel_crtc *crtc;
> -	u32 pipe_width = 0, total_width_in_range = 0, width_before_pipe_in_range = 0;
> +	unsigned int pipe_weight = 0, total_weight = 0, weight_before_pipe = 0;
>  	enum pipe for_pipe = to_intel_crtc(for_crtc)->pipe;
>  	struct intel_dbuf_state *new_dbuf_state =
>  		intel_atomic_get_new_dbuf_state(intel_state);
> @@ -4167,18 +4186,11 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
>  	 */
>  	ddb_range_size = hweight8(dbuf_slice_mask) * slice_size;
>  
> -	/*
> -	 * Watermark/ddb requirement highly depends upon width of the
> -	 * framebuffer, So instead of allocating DDB equally among pipes
> -	 * distribute DDB based on resolution/width of the display.
> -	 */
>  	total_slice_mask = dbuf_slice_mask;
>  	for_each_new_intel_crtc_in_state(intel_state, crtc, crtc_state, i) {
> -		const struct drm_display_mode *adjusted_mode =
> -			&crtc_state->hw.adjusted_mode;
>  		enum pipe pipe = crtc->pipe;
> -		int hdisplay, vdisplay;
> -		u32 pipe_dbuf_slice_mask;
> +		unsigned int weight;
> +		u8 pipe_dbuf_slice_mask;
>  
>  		if (!crtc_state->hw.active)
>  			continue;
> @@ -4205,14 +4217,13 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
>  		if (dbuf_slice_mask != pipe_dbuf_slice_mask)
>  			continue;
>  
> -		drm_mode_get_hv_timing(adjusted_mode, &hdisplay, &vdisplay);
> -
> -		total_width_in_range += hdisplay;
> +		weight = intel_crtc_ddb_weight(crtc_state);
> +		total_weight += weight;
>  
>  		if (pipe < for_pipe)
> -			width_before_pipe_in_range += hdisplay;
> +			weight_before_pipe += weight;
>  		else if (pipe == for_pipe)
> -			pipe_width = hdisplay;
> +			pipe_weight = weight;
>  	}
>  
>  	/*
> @@ -4227,9 +4238,8 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
>  			return ret;
>  	}
>  
> -	start = ddb_range_size * width_before_pipe_in_range / total_width_in_range;
> -	end = ddb_range_size *
> -		(width_before_pipe_in_range + pipe_width) / total_width_in_range;
> +	start = ddb_range_size * weight_before_pipe / total_weight;
> +	end = ddb_range_size * (weight_before_pipe + pipe_weight) / total_weight;
>  
>  	alloc->start = offset + start;
>  	alloc->end = offset + end;
> -- 
> 2.26.2
> 
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