You probably need to make the configuration for the mama4all. The easy way is to connect a USB keyboard, enter in a game and hit the <TAB> key.
You will see a menu, select the 1st option and configure your controller. To setup a button, hit <ENTER> on the keyboard then the controller button. To remove/del a setup, hit <ENTER> on the option you want to remove then <TAB><TAB>.
If this does not work, may be you need to config your Xin-Mo : http://blog.petrockblock.com/forums/topic/how-to-get-xin-mo-dual-arcade-working-with-retropie-easy-guide/