drm/i915: Extract intel_adjusted_rate()

Extract a small helper to calculate the downscaling
adjusted pixel rate/data rate/etc.

v2: Drop the plane visibility check and add a comment explaining why

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210401154043.19466-1-ville.syrjala@linux.intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
index c3f2962..07fcfec 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
+++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
@@ -133,25 +133,45 @@ intel_plane_destroy_state(struct drm_plane *plane,
        kfree(plane_state);
 }
 
-unsigned int intel_plane_pixel_rate(const struct intel_crtc_state *crtc_state,
-                                   const struct intel_plane_state *plane_state)
+static unsigned int intel_adjusted_rate(const struct drm_rect *src,
+                                       const struct drm_rect *dst,
+                                       unsigned int rate)
 {
        unsigned int src_w, src_h, dst_w, dst_h;
-       unsigned int pixel_rate = crtc_state->pixel_rate;
 
-       src_w = drm_rect_width(&plane_state->uapi.src) >> 16;
-       src_h = drm_rect_height(&plane_state->uapi.src) >> 16;
-       dst_w = drm_rect_width(&plane_state->uapi.dst);
-       dst_h = drm_rect_height(&plane_state->uapi.dst);
+       src_w = drm_rect_width(src) >> 16;
+       src_h = drm_rect_height(src) >> 16;
+       dst_w = drm_rect_width(dst);
+       dst_h = drm_rect_height(dst);
 
        /* Downscaling limits the maximum pixel rate */
        dst_w = min(src_w, dst_w);
        dst_h = min(src_h, dst_h);
 
-       return DIV_ROUND_UP_ULL(mul_u32_u32(pixel_rate, src_w * src_h),
+       return DIV_ROUND_UP_ULL(mul_u32_u32(rate, src_w * src_h),
                                dst_w * dst_h);
 }
 
+unsigned int intel_plane_pixel_rate(const struct intel_crtc_state *crtc_state,
+                                   const struct intel_plane_state *plane_state)
+{
+       /*
+        * Note we don't check for plane visibility here as
+        * we want to use this when calculating the cursor
+        * watermarks even if the cursor is fully offscreen.
+        * That depends on the src/dst rectangles being
+        * correctly populated whenever the watermark code
+        * considers the cursor to be visible, whether or not
+        * it is actually visible.
+        *
+        * See: intel_wm_plane_visible() and intel_check_cursor()
+        */
+
+       return intel_adjusted_rate(&plane_state->uapi.src,
+                                  &plane_state->uapi.dst,
+                                  crtc_state->pixel_rate);
+}
+
 unsigned int intel_plane_data_rate(const struct intel_crtc_state *crtc_state,
                                   const struct intel_plane_state *plane_state)
 {