Re: [PATCH v4] drm/i915/bxt: Implement Transition WM

[Paulo Zanoni <paulo.r.zanoni@intel.com>]

Em Qua, 2016-09-14 às 17:24 +0530, Kumar, Mahesh escreveu:
> From: Mahesh Kumar <mahesh1.kumar@intel.com>
> 
> This patch enables Transition WM for SKL+ platforms.
> 
> Transition WM are used if IPC is enabled, to decide, number of blocks
> to be fetched before reducing the priority of display to fetch from
> memory.
> 
> Changes since v1:
>  - Don't enable transition WM for GEN9 (Art/Paulo)
>  - Rebase to use fixed point 16.16 calculation
>  - Fix the use of selected result from latency level-0
> 
> Changes since v2:
>  - Fix transition WM enable condition
> 
> Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 60
> ++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 57 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c
> b/drivers/gpu/drm/i915/intel_pm.c
> index de2e738..4814a1a 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -2862,6 +2862,8 @@ bool ilk_disable_lp_wm(struct drm_device *dev)
>  
>  #define SKL_DDB_SIZE		896	/* in blocks */
>  #define BXT_DDB_SIZE		512
> +#define SKL_TRANS_WM_AMOUNT	10	/* tunable value */
> +#define SKL_TRANS_WM_MIN	14
>  #define SKL_SAGV_BLOCK_TIME	30 /* µs */
>  
>  /*
> @@ -3583,6 +3585,48 @@ static uint32_t
> skl_adjusted_plane_pixel_rate(const struct intel_crtc_state *cst
>  	return pixel_rate;
>  }
>  
> +static void skl_compute_plane_trans_wm(const struct drm_i915_private
> *dev_priv,
> +					struct skl_pipe_wm *pipe_wm,
> +					struct intel_plane_state
> *intel_pstate,
> +					uint32_t selected_result,
> +					uint32_t y_tile_min,
> +					bool y_tile)
> +{
> +	struct drm_plane_state *pstate = &intel_pstate->base;
> +	int id = skl_wm_plane_id(to_intel_plane(pstate->plane));
> +	uint16_t *out_blocks = &pipe_wm->trans_wm.plane_res_b[id];
> +	uint8_t *out_lines = &pipe_wm->trans_wm.plane_res_l[id];
> +	uint32_t trans_min = 0, trans_offset_blocks;
> +	uint32_t trans_y_tile_min = 0, res_blocks = 0;
> +	uint16_t trans_res_blocks = 0;
> +
> +	/* Keep Trans WM disabled for GEN9 */
> +	if (IS_GEN9(dev_priv))
> +		goto exit;

But the only platforms that call this function are gen9...


> +
> +	trans_min = SKL_TRANS_WM_MIN;
> +
> +	trans_offset_blocks = (trans_min + SKL_TRANS_WM_AMOUNT) <<
> 16;
> +
> +	if (y_tile) {
> +		trans_y_tile_min = 2 * y_tile_min;
> +		res_blocks = max(trans_y_tile_min, selected_result)
> +
> +			trans_offset_blocks;
> +	} else {
> +		res_blocks = selected_result + trans_offset_blocks;
> +	}
> +
> +	trans_res_blocks = DIV_ROUND_UP(res_blocks, 1 << 16) + 1;
> +
> +	/* WA BUG:1938466 add one block for non y-tile planes */
> +	if (!y_tile)
> +		trans_res_blocks += 1;
> +exit:
> +	*out_blocks = trans_res_blocks;
> +	*out_lines = 0;
> +}
> +
> +
>  static int skl_compute_plane_wm(const struct drm_i915_private
> *dev_priv,
>  				struct intel_crtc_state *cstate,
>  				struct intel_plane_state
> *intel_pstate,
> @@ -3709,6 +3753,9 @@ static int skl_compute_plane_wm(const struct
> drm_i915_private *dev_priv,
>  	*out_blocks = res_blocks;
>  	*out_lines = res_lines;
>  
> +	if (level == 0)
> +		skl_compute_plane_trans_wm(dev_priv, pipe_wm,
> intel_pstate,
> +				selected_result, y_tile_minimum,
> y_tiled);
>  	return 0;
>  }
>  
> @@ -3778,11 +3825,13 @@ skl_compute_linetime_wm(struct
> intel_crtc_state *cstate)
>  }
>  
>  static void skl_compute_transition_wm(struct intel_crtc_state
> *cstate,
> -				      struct skl_wm_level *trans_wm
> /* out */)
> +				      struct skl_wm_level *trans_wm,
> /* out */
> +				      struct skl_ddb_allocation
> *ddb)
>  {
>  	struct drm_crtc *crtc = cstate->base.crtc;
>  	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
>  	struct intel_plane *intel_plane;
> +	enum pipe pipe = to_intel_crtc(crtc)->pipe;
>  
>  	if (!cstate->base.active)
>  		return;
> @@ -3790,8 +3839,13 @@ static void skl_compute_transition_wm(struct
> intel_crtc_state *cstate,
>  	/* Until we know more, just disable transition WMs */
>  	for_each_intel_plane_on_crtc(crtc->dev, intel_crtc,
> intel_plane) {
>  		int i = skl_wm_plane_id(intel_plane);
> +		uint16_t plane_ddb = skl_ddb_entry_size(&ddb-
> >plane[pipe][i]);
> +		uint16_t trans_res_blocks = trans_wm-
> >plane_res_b[i];
>  
> -		trans_wm->plane_en[i] = false;
> +		if ((trans_res_blocks > 0) && (trans_res_blocks <=
> plane_ddb))
> +			trans_wm->plane_en[i] = true;
> +		else
> +			trans_wm->plane_en[i] = false;
>  	}
>  }
>  
> @@ -3822,7 +3876,7 @@ static int skl_build_pipe_wm(struct
> intel_crtc_state *cstate,
>  
>  	pipe_wm->linetime = skl_compute_linetime_wm(cstate);
>  
> -	skl_compute_transition_wm(cstate, &pipe_wm->trans_wm);
> +	skl_compute_transition_wm(cstate, &pipe_wm->trans_wm, ddb);
>  
>  	return 0;
>  }
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