backend-drm: add DRM_FORMAT_MOD_INVALID to modifier sets when no modifiers are supported

From now on, when we can't know the modifiers supported for a certain
format, we add DRM_FORMAT_MOD_INVALID to its modifier set.

There is some parts where nothing is being added an others where
DRM_FORMAT_MOD_LINEAR is being added, so fix them.

Signed-off-by: Leandro Ribeiro <leandro.ribeiro@collabora.com>

libweston/backend-drm/drm-gbm.c

@@ -195,8 +195,8 @@ create_gbm_surface(struct gbm_device *gbm, struct drm_output *output)
 	}
 
 #ifdef HAVE_GBM_MODIFIERS
-	modifiers = weston_drm_format_get_modifiers(fmt, &num_modifiers);
-	if (num_modifiers > 0) {
+	if (!weston_drm_format_has_modifier(fmt, DRM_FORMAT_MOD_INVALID)) {
+		modifiers = weston_drm_format_get_modifiers(fmt, &num_modifiers);
 		output->gbm_surface =
 			gbm_surface_create_with_modifiers(gbm,
 							  mode->width, mode->height,

libweston/backend-drm/drm-virtual.c

@@ -94,7 +94,7 @@ drm_virtual_plane_create(struct drm_backend *b, struct drm_output *output)
 {
 	struct drm_plane *plane;
 	struct weston_drm_format *fmt;
-	int ret;
+	uint64_t mod;
 
 	plane = zalloc(sizeof(*plane));
 	if (!plane) {
@@ -112,11 +112,16 @@ drm_virtual_plane_create(struct drm_backend *b, struct drm_output *output)
 	if (!fmt)
 		goto err;
 
-	if ((output->gbm_bo_flags & GBM_BO_USE_LINEAR) && b->fb_modifiers) {
-		ret = weston_drm_format_add_modifier(fmt, DRM_FORMAT_MOD_LINEAR);
-		if (ret < 0)
-			goto err;
-	}
+	/* If output supports linear modifier, we add it to the plane.
+	 * Otherwise we add DRM_FORMAT_MOD_INVALID, as explicit modifiers
+	 * are not supported. */
+	if ((output->gbm_bo_flags & GBM_BO_USE_LINEAR) && b->fb_modifiers)
+		mod = DRM_FORMAT_MOD_LINEAR;
+	else
+		mod = DRM_FORMAT_MOD_INVALID;
+
+	if (weston_drm_format_add_modifier(fmt, mod) < 0)
+		goto err;
 
 	weston_plane_init(&plane->base, b->compositor, 0, 0);
 	wl_list_insert(&b->plane_list, &plane->link);

libweston/backend-drm/drm.c

@@ -760,6 +760,7 @@ drm_plane_create(struct drm_backend *b, const drmModePlane *kplane,
 	struct drm_plane *plane;
 	drmModeObjectProperties *props;
 	uint64_t *zpos_range_values;
+	struct weston_drm_format *fmt;
 
 	plane = zalloc(sizeof(*plane));
 	if (!plane) {
@@ -816,7 +817,14 @@ drm_plane_create(struct drm_backend *b, const drmModePlane *kplane,
 		plane->type = type;
 		plane->zpos_max = DRM_PLANE_ZPOS_INVALID_PLANE;
 		plane->zpos_min = DRM_PLANE_ZPOS_INVALID_PLANE;
-		if (!weston_drm_format_array_add_format(&plane->formats, format))
+
+		/* Without universal planes support we can't tell the formats
+		 * and modifiers that the plane support, as we don't know
+		 * anything about the planes. So modifiers are not supported. */
+		fmt = weston_drm_format_array_add_format(&plane->formats, format);
+		if (!fmt)
+			goto err;
+		if (!weston_drm_format_add_modifier(fmt, DRM_FORMAT_MOD_INVALID))
 			goto err;
 	}
 

libweston/backend-drm/kms.c

@@ -483,7 +483,7 @@ drm_plane_populate_formats(struct drm_plane *plane, const drmModePlane *kplane,
 		}
 
 		if (fmt->modifiers.size == 0) {
-			ret = weston_drm_format_add_modifier(fmt, DRM_FORMAT_MOD_LINEAR);
+			ret = weston_drm_format_add_modifier(fmt, DRM_FORMAT_MOD_INVALID);
 			if (ret < 0)
 				goto out;
 		}
@@ -500,7 +500,7 @@ fallback:
 							 kplane->formats[i]);
 		if (!fmt)
 			return -1;
-		ret = weston_drm_format_add_modifier(fmt, DRM_FORMAT_MOD_LINEAR);
+		ret = weston_drm_format_add_modifier(fmt, DRM_FORMAT_MOD_INVALID);
 		if (ret < 0)
 			return -1;
 	}