backend: add error messages in attach_render impls

backend/drm/renderer.c

@@ -114,7 +114,7 @@ bool drm_surface_make_current(struct wlr_drm_surface *surf,
 	}
 
 	if (!wlr_renderer_bind_buffer(surf->renderer->wlr_rend, surf->back_buffer)) {
-		wlr_log(WLR_ERROR, "Failed to attach buffer to renderer");
+		wlr_log(WLR_ERROR, "Failed to bind buffer to renderer");
 		return false;
 	}
 

backend/headless/output.c

@@ -46,11 +46,13 @@ static bool output_attach_render(struct wlr_output *wlr_output,
 	wlr_buffer_unlock(output->back_buffer);
 	output->back_buffer = wlr_swapchain_acquire(output->swapchain, buffer_age);
 	if (!output->back_buffer) {
+		wlr_log(WLR_ERROR, "Failed to acquire swapchain buffer");
 		return false;
 	}
 
 	if (!wlr_renderer_bind_buffer(output->backend->renderer,
 			output->back_buffer)) {
+		wlr_log(WLR_ERROR, "Failed to bind buffer to renderer");
 		return false;
 	}
 

backend/wayland/output.c

@@ -119,11 +119,13 @@ static bool output_attach_render(struct wlr_output *wlr_output,
 	wlr_buffer_unlock(output->back_buffer);
 	output->back_buffer = wlr_swapchain_acquire(output->swapchain, buffer_age);
 	if (!output->back_buffer) {
+		wlr_log(WLR_ERROR, "Failed to acquire swapchain buffer");
 		return false;
 	}
 
 	if (!wlr_renderer_bind_buffer(output->backend->renderer,
 			output->back_buffer)) {
+		wlr_log(WLR_ERROR, "Failed to bind buffer to renderer");
 		return false;
 	}
 

backend/x11/output.c

@@ -101,10 +101,12 @@ static bool output_attach_render(struct wlr_output *wlr_output,
 	wlr_buffer_unlock(output->back_buffer);
 	output->back_buffer = wlr_swapchain_acquire(output->swapchain, buffer_age);
 	if (!output->back_buffer) {
+		wlr_log(WLR_ERROR, "Failed to acquire swapchain buffer");
 		return false;
 	}
 
 	if (!wlr_renderer_bind_buffer(x11->renderer, output->back_buffer)) {
+		wlr_log(WLR_ERROR, "Failed to bind buffer to renderer");
 		return false;
 	}