drm/virtio: log error responses

If we got an error response code from the host, print it to the log.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20181219122708.4586-2-kraxel@redhat.com

drivers/gpu/drm/virtio/virtgpu_vq.c

@@ -192,8 +192,16 @@ void virtio_gpu_dequeue_ctrl_func(struct work_struct *work)
 
 	list_for_each_entry_safe(entry, tmp, &reclaim_list, list) {
 		resp = (struct virtio_gpu_ctrl_hdr *)entry->resp_buf;
-		if (resp->type != cpu_to_le32(VIRTIO_GPU_RESP_OK_NODATA))
+		if (resp->type != cpu_to_le32(VIRTIO_GPU_RESP_OK_NODATA)) {
+			if (resp->type >= cpu_to_le32(VIRTIO_GPU_RESP_ERR_UNSPEC)) {
+				struct virtio_gpu_ctrl_hdr *cmd;
+				cmd = (struct virtio_gpu_ctrl_hdr *)entry->buf;
+				DRM_ERROR("response 0x%x (command 0x%x)\n",
+					  le32_to_cpu(resp->type),
+					  le32_to_cpu(cmd->type));
+			} else
 				DRM_DEBUG("response 0x%x\n", le32_to_cpu(resp->type));
+		}
 		if (resp->flags & cpu_to_le32(VIRTIO_GPU_FLAG_FENCE)) {
 			u64 f = le64_to_cpu(resp->fence_id);