kms: Allow passing framebuffer damage metadata

This commit adds support to atomic KMS backend for optional plane property
prop_fb_damage_clips. Some drivers (e.g. EVDI) take advantage of this
property and process only updated regions of the screen instead of
processing the full frame. This can save system resources.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1879>

src/backends/native/meta-kms-impl-device-atomic.c

@@ -416,6 +416,8 @@ process_plane_assignment (MetaKmsImplDevice  *impl_device,
   MetaKmsPlaneAssignment *plane_assignment = update_entry;
   MetaKmsPlane *plane = plane_assignment->plane;
   MetaDrmBuffer *buffer;
+  MetaKmsFbDamage *fb_damage;
+  uint32_t prop_id;
 
   buffer = plane_assignment->buffer;
 
@@ -539,6 +541,32 @@ process_plane_assignment (MetaKmsImplDevice  *impl_device,
         return FALSE;
     }
 
+  fb_damage = plane_assignment->fb_damage;
+  if (fb_damage &&
+      meta_kms_plane_get_prop_id (plane,
+                                  META_KMS_PLANE_PROP_FB_DAMAGE_CLIPS_ID))
+    {
+      meta_topic (META_DEBUG_KMS,
+                  "[atomic] Setting %d damage clips on %u",
+                  fb_damage->n_rects,
+                  meta_kms_plane_get_id (plane));
+
+      prop_id = store_new_blob (impl_device,
+                                blob_ids,
+                                fb_damage->rects,
+                                fb_damage->n_rects *
+                                sizeof (struct drm_mode_rect),
+                                error);
+      if (!prop_id)
+        return FALSE;
+
+      if (!add_plane_property (impl_device,
+                               plane, req,
+                               META_KMS_PLANE_PROP_FB_DAMAGE_CLIPS_ID,
+                               prop_id,
+                               error))
+        return FALSE;
+    }
   return TRUE;
 }
 

src/backends/native/meta-kms-plane-private.h

@@ -41,6 +41,7 @@ typedef enum _MetaKmsPlaneProp
   META_KMS_PLANE_PROP_CRTC_H,
   META_KMS_PLANE_PROP_FB_ID,
   META_KMS_PLANE_PROP_CRTC_ID,
+  META_KMS_PLANE_PROP_FB_DAMAGE_CLIPS_ID,
   META_KMS_PLANE_N_PROPS
 } MetaKmsPlaneProp;
 

src/backends/native/meta-kms-plane.c

@@ -446,6 +446,11 @@ init_properties (MetaKmsPlane            *plane,
           .name = "CRTC_ID",
           .type = DRM_MODE_PROP_OBJECT,
         },
+      [META_KMS_PLANE_PROP_FB_DAMAGE_CLIPS_ID] =
+        {
+          .name = "FB_DAMAGE_CLIPS",
+          .type = DRM_MODE_PROP_BLOB,
+        },
     }
   };
 

src/backends/native/meta-kms-update-private.h

@@ -34,6 +34,12 @@ typedef struct _MetaKmsFeedback
   GError *error;
 } MetaKmsFeedback;
 
+typedef struct _MetaKmsFbDamage
+{
+  struct drm_mode_rect *rects;
+  int n_rects;
+} MetaKmsFbDamage;
+
 typedef struct _MetaKmsPlaneAssignment
 {
   MetaKmsUpdate *update;
@@ -43,6 +49,7 @@ typedef struct _MetaKmsPlaneAssignment
   MetaFixed16Rectangle src_rect;
   MetaRectangle dst_rect;
   MetaKmsAssignPlaneFlag flags;
+  MetaKmsFbDamage *fb_damage;
 
   uint64_t rotation;
 

src/backends/native/meta-kms-update.c

@@ -129,9 +129,17 @@ meta_kms_feedback_get_error (const MetaKmsFeedback *feedback)
   return feedback->error;
 }
 
+static void
+meta_kms_fb_damage_free (MetaKmsFbDamage *fb_damage)
+{
+  g_free (fb_damage->rects);
+  g_free (fb_damage);
+}
+
 static void
 meta_kms_plane_assignment_free (MetaKmsPlaneAssignment *plane_assignment)
 {
+  g_clear_pointer (&plane_assignment->fb_damage, meta_kms_fb_damage_free);
   g_free (plane_assignment);
 }
 
@@ -456,6 +464,33 @@ meta_kms_update_set_custom_page_flip (MetaKmsUpdate             *update,
   update->custom_page_flip = custom_page_flip;
 }
 
+void
+meta_kms_plane_assignment_set_fb_damage (MetaKmsPlaneAssignment *plane_assignment,
+                                         const int              *rectangles,
+                                         int                     n_rectangles)
+{
+  MetaKmsFbDamage *fb_damage;
+  struct drm_mode_rect *mode_rects;
+  int i;
+
+  mode_rects = g_new0 (struct drm_mode_rect, n_rectangles);
+  for (i = 0; i < n_rectangles; ++i)
+    {
+      mode_rects[i].x1 = rectangles[i * 4];
+      mode_rects[i].y1 = rectangles[i * 4 + 1];
+      mode_rects[i].x2 = mode_rects[i].x1 + rectangles[i * 4 + 2];
+      mode_rects[i].y2 = mode_rects[i].y1 + rectangles[i * 4 + 3];
+    }
+
+  fb_damage = g_new0 (MetaKmsFbDamage, 1);
+  *fb_damage = (MetaKmsFbDamage) {
+    .rects = mode_rects,
+    .n_rects = n_rectangles,
+  };
+
+  plane_assignment->fb_damage = fb_damage;
+}
+
 void
 meta_kms_plane_assignment_set_rotation (MetaKmsPlaneAssignment *plane_assignment,
                                         uint64_t                rotation)

src/backends/native/meta-kms-update.h

@@ -115,6 +115,10 @@ void meta_kms_update_set_crtc_gamma (MetaKmsUpdate  *update,
                                      const uint16_t *green,
                                      const uint16_t *blue);
 
+void meta_kms_plane_assignment_set_fb_damage (MetaKmsPlaneAssignment *plane_assignment,
+                                              const int              *rectangles,
+                                              int                     n_rectangles);
+
 MetaKmsPlaneAssignment * meta_kms_update_assign_plane (MetaKmsUpdate          *update,
                                                        MetaKmsCrtc            *crtc,
                                                        MetaKmsPlane           *plane,