[worker] Enable android usb before starting mtpd. JB#41748

While in configfs we must start mtpd (so that it writes endpoint config)
before we can enable udc, apparently the reverse applies at least in
some devices utilizing android usb.

When android usb backend is in use, do the gadget configuration before
starting mtpd.
Signed-off-by: Simo Piiroinen <simo.piiroinen@jollamobile.com>

src/usb_moded-worker.c

@@ -531,7 +531,9 @@ worker_switch_to_mode(const char *mode)
          * as they will use the worker_get_usb_mode_data function */
         worker_set_usb_mode_data(data);
 
-        if( worker_mode_is_mtp_mode(mode) ) {
+        /* When dealing with configfs, we can't enable UDC without
+         * already having mtpd running */
+        if( worker_mode_is_mtp_mode(mode) && configfs_in_use() ) {
             if( !worker_start_mtpd() )
                 goto FAILED;
         }
@@ -542,6 +544,14 @@ worker_switch_to_mode(const char *mode)
         if( !modesetting_enter_dynamic_mode() )
             goto FAILED;
 
+        /* When dealing with android usb, it must be enabled before
+         * we can start mtpd. Assumption is that the same applies
+         * when using kernel modules. */
+        if( worker_mode_is_mtp_mode(mode) && !configfs_in_use() ) {
+            if( !worker_start_mtpd() )
+                goto FAILED;
+        }
+
         goto SUCCESS;
     }