drm: check for PRIME support

PRIME support for buffer sharing has become mandatory since the renderer
rewrite. Make sure we check for the appropriate capabilities in backend,
allocator and renderer.

See also #2819.

backend/drm/drm.c

@@ -30,14 +30,13 @@
 
 bool check_drm_features(struct wlr_drm_backend *drm) {
 	uint64_t cap;
-	if (drm->parent) {
+	if (drmGetCap(drm->fd, DRM_CAP_PRIME, &cap) ||
-		if (drmGetCap(drm->fd, DRM_CAP_PRIME, &cap) ||
+			!(cap & DRM_PRIME_CAP_IMPORT)) {
-				!(cap & DRM_PRIME_CAP_IMPORT)) {
+		wlr_log(WLR_ERROR, "PRIME import not supported");
-			wlr_log(WLR_ERROR,
+		return false;
-				"PRIME import not supported on secondary GPU");
+	}
-			return false;
-		}
 
+	if (drm->parent) {
 		if (drmGetCap(drm->parent->fd, DRM_CAP_PRIME, &cap) ||
 				!(cap & DRM_PRIME_CAP_EXPORT)) {
 			wlr_log(WLR_ERROR,

render/gbm_allocator.c

@@ -160,6 +160,13 @@ static struct wlr_gbm_allocator *get_gbm_alloc_from_alloc(
 }
 
 struct wlr_gbm_allocator *wlr_gbm_allocator_create(int fd) {
+	uint64_t cap;
+	if (drmGetCap(fd, DRM_CAP_PRIME, &cap) ||
+			!(cap & DRM_PRIME_CAP_EXPORT)) {
+		wlr_log(WLR_ERROR, "PRIME export not supported");
+		return NULL;
+	}
+
 	struct wlr_gbm_allocator *alloc = calloc(1, sizeof(*alloc));
 	if (alloc == NULL) {
 		return NULL;

render/gles2/renderer.c

@@ -746,6 +746,11 @@ struct wlr_renderer *wlr_gles2_renderer_create(struct wlr_egl *egl) {
 	wlr_log(WLR_INFO, "GL renderer: %s", glGetString(GL_RENDERER));
 	wlr_log(WLR_INFO, "Supported GLES2 extensions: %s", exts_str);
 
+	if (!renderer->egl->exts.image_dmabuf_import_ext) {
+		wlr_log(WLR_ERROR, "EGL_EXT_image_dma_buf_import not supported");
+		free(renderer);
+		return NULL;
+	}
 	if (!check_gl_ext(exts_str, "GL_EXT_texture_format_BGRA8888")) {
 		wlr_log(WLR_ERROR, "BGRA8888 format not supported by GLES2");
 		free(renderer);