(3.0 version) some Mackie-emulation systems (e.g. euphonix) send zero for the tick count when the jog wheel is moved, so accomodate this by pretending that they reported 1 tick

git-svn-id: svn://localhost/ardour2/branches/3.0@7907 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/surfaces/mackie/mackie_port.cc

@@ -444,6 +444,12 @@ void MackiePort::handle_midi_any (MIDI::Parser &, MIDI::byte * raw_bytes, size_t
 				state.sign = ( raw_bytes[2] & 0x40 ) == 0 ? 1 : -1; 
 				// bytes[2] & 0b00111111 (0x3f) gives delta
 				state.ticks = ( raw_bytes[2] & 0x3f);
+                                if (state.ticks == 0) {
+                                        /* euphonix and perhaps other devices send zero
+                                           when they mean 1, we think.
+                                        */
+                                        state.ticks = 1;
+                                }
 				state.delta = float( state.ticks ) / float( 0x3f );
 				
 				/*