raspinfo: warn for legacy video requiring non-default userland package

Author: macmpi

raspinfo/raspinfo

@@ -87,9 +87,14 @@ display_info_drm() {
 
 display_info_legacy() {
    # Legacy mode
-   echo "Running Legacy framebuffer"
+   echo "Running Legacy framebuffer (unsupported)"
    echo
 
+   if ! command -v tvservice > /dev/null; then
+	echo "Please install Legacy userland package (tvservice)"
+	return 1
+   fi
+
    for card in `seq 0 9`;
    do
       F="/dev/fb${card}"