DZ_XMIT_SIZE 286 drivers/tty/serial/dz.c xmit->tail = (xmit->tail + 1) & (DZ_XMIT_SIZE - 1); DZ_XMIT_SIZE 128 drivers/tty/serial/dz.h #define DZ_WAKEUP_CHARS DZ_XMIT_SIZE/4