Merge pull request #1286 from emersion/drm-no-crtc

backend/drm: better handle GPUs without CRTCs

backend/drm/drm.c

@@ -156,6 +156,11 @@ bool init_drm_resources(struct wlr_drm_backend *drm) {
 	wlr_log(WLR_INFO, "Found %d DRM CRTCs", res->count_crtcs);
 
 	drm->num_crtcs = res->count_crtcs;
+	if (drm->num_crtcs == 0) {
+		drmModeFreeResources(res);
+		return true;
+	}
+
 	drm->crtcs = calloc(drm->num_crtcs, sizeof(drm->crtcs[0]));
 	if (!drm->crtcs) {
 		wlr_log_errno(WLR_ERROR, "Allocation failed");
@@ -433,9 +438,9 @@ static void realloc_planes(struct wlr_drm_backend *drm, const uint32_t *crtc_in,
 			continue;
 		}
 
-		uint32_t possible[drm->num_type_planes[type]];
+		uint32_t possible[drm->num_type_planes[type] + 1];
-		uint32_t crtc[drm->num_crtcs];
+		uint32_t crtc[drm->num_crtcs + 1];
-		uint32_t crtc_res[drm->num_crtcs];
+		uint32_t crtc_res[drm->num_crtcs + 1];
 
 		for (size_t i = 0; i < drm->num_type_planes[type]; ++i) {
 			possible[i] = drm->type_planes[type][i].possible_crtcs;
@@ -1160,7 +1165,7 @@ void scan_drm_connectors(struct wlr_drm_backend *drm) {
 		}
 	}
 
-	bool changed_outputs[wl_list_length(&drm->outputs)];
+	bool changed_outputs[wl_list_length(&drm->outputs) + 1];
 	memset(changed_outputs, false, sizeof(changed_outputs));
 	for (size_t i = 0; i < new_outputs_len; ++i) {
 		struct wlr_drm_connector *conn = new_outputs[i];