Re: [PATCH 4/9] drm/i915: Allocate enough DDB for the cursor

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

On Tue, Mar 12, 2019 at 10:58:39PM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Currently we just assume that 32 or 8 blocks of ddb is sufficient
> for the cursor. The 32 might be, but the 8 is certainly not. The
> minimum we need is at least what level 0 watermarks need, but that
> is a bit restrictive, so instead let's calculate what level 7
> would need for a 256x256 cursor. We'll use that to determine the
> fixed ddb allocation for the cursor. This way the cursor will never
> be responsible for missing out on deeper power saving states.
> 
> Cc: Neel Desai <neel.desai@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 33 ++++++++++++++++++++++++++++-----
>  1 file changed, 28 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 9e7b4412f7a8..ae9a0ce4dcb9 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3924,12 +3924,35 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
>  	alloc->end = ddb_size * (width_before_pipe + pipe_width) / total_width;
>  }
>  
> -static unsigned int skl_cursor_allocation(int num_active)
> +static int skl_compute_wm_params(const struct intel_crtc_state *crtc_state,
> +				 int width, const struct drm_format_info *format,
> +				 u64 modifier, unsigned int rotation,
> +				 u32 plane_pixel_rate, struct skl_wm_params *wp,
> +				 int color_plane);
> +static void skl_compute_plane_wm(const struct intel_crtc_state *cstate,
> +				 int level,
> +				 const struct skl_wm_params *wp,
> +				 const struct skl_wm_level *result_prev,
> +				 struct skl_wm_level *result /* out */);
> +
> +static unsigned int
> +skl_cursor_allocation(const struct intel_crtc_state *crtc_state,
> +		      int num_active)
>  {
> -	if (num_active == 1)
> -		return 32;
> +	struct skl_wm_level wm = {};
> +	struct skl_wm_params wp;
> +	int ret;
> +
> +	ret = skl_compute_wm_params(crtc_state, 256,
> +				    drm_format_info(DRM_FORMAT_ARGB8888),
> +				    DRM_FORMAT_MOD_LINEAR,
> +				    DRM_MODE_ROTATE_0,
> +				    crtc_state->pixel_rate, &wp, 0);
> +	WARN_ON(ret);
> +
> +	skl_compute_plane_wm(crtc_state, 7, &wp, &wm, &wm);

Hmm. This borked if latency[7]==0. I guess I actually need to loop
here...

>  
> -	return 8;
> +	return max_t(int, num_active == 1 ? 32 : 8, wm.min_ddb_alloc);
>  }
>  
>  static void skl_ddb_entry_init_from_hw(struct drm_i915_private *dev_priv,
> @@ -4354,7 +4377,7 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *cstate,
>  		return 0;
>  
>  	/* Allocate fixed number of blocks for cursor. */
> -	total[PLANE_CURSOR] = skl_cursor_allocation(num_active);
> +	total[PLANE_CURSOR] = skl_cursor_allocation(cstate, num_active);
>  	alloc_size -= total[PLANE_CURSOR];
>  	cstate->wm.skl.plane_ddb_y[PLANE_CURSOR].start =
>  		alloc->end - total[PLANE_CURSOR];
> -- 
> 2.19.2

-- 
Ville Syrjälä
Intel
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