HelenOS sources

DEVICE_USABLE     704 uspace/srv/devman/driver.c 		dev->state = DEVICE_USABLE;
DEVICE_USABLE     572 uspace/srv/devman/drv_conn.c 			if (dev_state == DEVICE_USABLE)
DEVICE_USABLE     383 uspace/srv/devman/fun.c 			if (dev_state == DEVICE_USABLE) {
DEVICE_USABLE     472 uspace/srv/devman/fun.c 	if (dev_state == DEVICE_USABLE) {
HelenOS homepage, sources at GitHub