HelenOS sources

client_connection  913 uspace/srv/hid/console/console.c 	async_set_fallback_port_handler(client_connection, NULL);
client_connection  902 uspace/srv/hid/input/input.c 	async_set_fallback_port_handler(client_connection, NULL);
client_connection  482 uspace/srv/hid/output/output.c 	async_set_fallback_port_handler(client_connection, NULL);
client_connection  875 uspace/srv/hid/remcons/remcons.c 	async_set_fallback_port_handler(client_connection, NULL);
client_connection  483 uspace/srv/hid/rfb/main.c 	async_set_fallback_port_handler(client_connection, &rfb);
HelenOS homepage, sources at GitHub