stdma_try_lock
wait_event(stdma_wait, stdma_try_lock(handler, data));
EXPORT_SYMBOL(stdma_try_lock);
int stdma_try_lock(irq_handler_t, void *);
if (!stdma_try_lock(floppy_irq, NULL)) {
return stdma_try_lock(scsi_falcon_intr, instance);