1 files changed, 76 insertions, 12 deletions

diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 672c655c7a8e..a28b22fdd7a4 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -140,6 +140,25 @@
  *     DRM_FORMAT_MOD_LINEAR. Before linux kernel release v5.1 there have been
  *     various bugs in this area with inconsistencies between the capability
  *     flag and per-plane properties.
+ *
+ * SIZE_HINTS:
+ *     Blob property which contains the set of recommended plane size
+ *     which can used for simple "cursor like" use cases (eg. no scaling).
+ *     Using these hints frees userspace from extensive probing of
+ *     supported plane sizes through atomic/setcursor ioctls.
+ *
+ *     The blob contains an array of struct drm_plane_size_hint, in
+ *     order of preference. For optimal usage userspace should pick
+ *     the first size that satisfies its own requirements.
+ *
+ *     Drivers should only attach this property to planes that
+ *     support a very limited set of sizes.
+ *
+ *     Note that property value 0 (ie. no blob) is reserved for potential
+ *     future use. Current userspace is expected to ignore the property
+ *     if the value is 0, and fall back to some other means (eg.
+ *     &DRM_CAP_CURSOR_WIDTH and &DRM_CAP_CURSOR_HEIGHT) to determine
+ *     the appropriate plane size to use.
  */
 
 static unsigned int drm_num_planes(struct drm_device *dev)
@@ -858,8 +877,17 @@ int drm_mode_getplane(struct drm_device *dev, void *data,
 	return 0;
 }
 
-int drm_plane_check_pixel_format(struct drm_plane *plane,
-				 u32 format, u64 modifier)
+/**
+ * drm_plane_has_format - Check whether the plane supports this format and modifier combination
+ * @plane: drm plane
+ * @format: pixel format (DRM_FORMAT_*)
+ * @modifier: data layout modifier
+ *
+ * Returns:
+ * Whether the plane supports the specified format and modifier combination.
+ */
+bool drm_plane_has_format(struct drm_plane *plane,
+			  u32 format, u64 modifier)
 {
 	unsigned int i;
 
@@ -868,25 +896,26 @@ int drm_plane_check_pixel_format(struct drm_plane *plane,
 			break;
 	}
 	if (i == plane->format_count)
-		return -EINVAL;
+		return false;
 
 	if (plane->funcs->format_mod_supported) {
 		if (!plane->funcs->format_mod_supported(plane, format, modifier))
-			return -EINVAL;
+			return false;
 	} else {
 		if (!plane->modifier_count)
-			return 0;
+			return true;
 
 		for (i = 0; i < plane->modifier_count; i++) {
 			if (modifier == plane->modifiers[i])
 				break;
 		}
 		if (i == plane->modifier_count)
-			return -EINVAL;
+			return false;
 	}
 
-	return 0;
+	return true;
 }
+EXPORT_SYMBOL(drm_plane_has_format);
 
 static int __setplane_check(struct drm_plane *plane,
 			    struct drm_crtc *crtc,
@@ -905,12 +934,10 @@ static int __setplane_check(struct drm_plane *plane,
 	}
 
 	/* Check whether this plane supports the fb pixel format. */
-	ret = drm_plane_check_pixel_format(plane, fb->format->format,
-					   fb->modifier);
-	if (ret) {
+	if (!drm_plane_has_format(plane, fb->format->format, fb->modifier)) {
 		DRM_DEBUG_KMS("Invalid pixel format %p4cc, modifier 0x%llx\n",
 			      &fb->format->format, fb->modifier);
-		return ret;
+		return -EINVAL;
 	}
 
 	/* Give drivers some help against integer overflows */
@@ -945,7 +972,7 @@ bool drm_any_plane_has_format(struct drm_device *dev,
 	struct drm_plane *plane;
 
 	drm_for_each_plane(plane, dev) {
-		if (drm_plane_check_pixel_format(plane, format, modifier) == 0)
+		if (drm_plane_has_format(plane, format, modifier))
 			return true;
 	}
 
@@ -1729,3 +1756,40 @@ int drm_plane_create_scaling_filter_property(struct drm_plane *plane,
 	return 0;
 }
 EXPORT_SYMBOL(drm_plane_create_scaling_filter_property);
+
+/**
+ * drm_plane_add_size_hints_property - create a size hints property
+ *
+ * @plane: drm plane
+ * @hints: size hints
+ * @num_hints: number of size hints
+ *
+ * Create a size hints property for the plane.
+ *
+ * RETURNS:
+ * Zero for success or -errno
+ */
+int drm_plane_add_size_hints_property(struct drm_plane *plane,
+				      const struct drm_plane_size_hint *hints,
+				      int num_hints)
+{
+	struct drm_device *dev = plane->dev;
+	struct drm_mode_config *config = &dev->mode_config;
+	struct drm_property_blob *blob;
+
+	/* extending to other plane types needs actual thought */
+	if (drm_WARN_ON(dev, plane->type != DRM_PLANE_TYPE_CURSOR))
+		return -EINVAL;
+
+	blob = drm_property_create_blob(dev,
+					array_size(sizeof(hints[0]), num_hints),
+					hints);
+	if (IS_ERR(blob))
+		return PTR_ERR(blob);
+
+	drm_object_attach_property(&plane->base, config->size_hints_property,
+				   blob->base.id);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_plane_add_size_hints_property);