Re: [PATCH 02/10] drm/i915/xe3lpd: Adjust watermark calculations

["Govindapillai, Vinod" <vinod.govindapillai@intel.com>]

On Tue, 2024-10-08 at 15:37 -0700, Matt Atwood wrote:
> From: Matt Roper <matthew.d.roper@intel.com>
> 
> Xe3 makes a couple minor tweaks to the watermark algorithm's block count
> calculations.
> 
> Bspec: 68985
> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com>
> ---
>  drivers/gpu/drm/i915/display/skl_watermark.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 

Looks good to me as per Bspec 68985

Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>

> diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c
> b/drivers/gpu/drm/i915/display/skl_watermark.c
> index 6e1f04d5ef47..31de33e868df 100644
> --- a/drivers/gpu/drm/i915/display/skl_watermark.c
> +++ b/drivers/gpu/drm/i915/display/skl_watermark.c
> @@ -718,7 +718,7 @@ 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);
> +                                int color_plane, unsigned int pan_x);
>  
>  static void skl_compute_plane_wm(const struct intel_crtc_state *crtc_state,
>                                  struct intel_plane *plane,
> @@ -765,7 +765,7 @@ skl_cursor_allocation(const struct intel_crtc_state *crtc_state,
>                                     drm_format_info(DRM_FORMAT_ARGB8888),
>                                     DRM_FORMAT_MOD_LINEAR,
>                                     DRM_MODE_ROTATE_0,
> -                                   crtc_state->pixel_rate, &wp, 0);
> +                                   crtc_state->pixel_rate, &wp, 0, 0);
>         drm_WARN_ON(&i915->drm, ret);
>  
>         for (level = 0; level < i915->display.wm.num_levels; level++) {
> @@ -1742,7 +1742,7 @@ 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)
> +                     int color_plane, unsigned int pan_x)
>  {
>         struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
>         struct drm_i915_private *i915 = to_i915(crtc->base.dev);
> @@ -1803,7 +1803,9 @@ skl_compute_wm_params(const struct intel_crtc_state *crtc_state,
>                                            wp->y_min_scanlines,
>                                            wp->dbuf_block_size);
>  
> -               if (DISPLAY_VER(i915) >= 10)
> +               if (DISPLAY_VER(i915) >= 30)
> +                       interm_pbpl += (pan_x != 0);
> +               else if (DISPLAY_VER(i915) >= 10)
>                         interm_pbpl++;
>  
>                 wp->plane_blocks_per_line = div_fixed16(interm_pbpl,
> @@ -1845,7 +1847,8 @@ skl_compute_plane_wm_params(const struct intel_crtc_state *crtc_state,
>                                      fb->format, fb->modifier,
>                                      plane_state->hw.rotation,
>                                      intel_plane_pixel_rate(crtc_state, plane_state),
> -                                    wp, color_plane);
> +                                    wp, color_plane,
> +                                    plane_state->uapi.src.x1);
>  }
>  
>  static bool skl_wm_has_lines(struct drm_i915_private *i915, int level)
> @@ -1909,7 +1912,10 @@ static void skl_compute_plane_wm(const struct intel_crtc_state *crtc_state,
>                 }
>         }
>  
> -       blocks = fixed16_to_u32_round_up(selected_result) + 1;
> +       blocks = fixed16_to_u32_round_up(selected_result);
> +       if (DISPLAY_VER(i915) < 30)
> +               blocks++;
> +
>         /*
>          * Lets have blocks at minimum equivalent to plane_blocks_per_line
>          * as there will be at minimum one line for lines configuration. This