diff options
Diffstat (limited to 'sys/dev/uart')
| -rw-r--r-- | sys/dev/uart/uart_dev_ns8250.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/sys/dev/uart/uart_dev_ns8250.c b/sys/dev/uart/uart_dev_ns8250.c index 5d56a68..eb36da1 100644 --- a/sys/dev/uart/uart_dev_ns8250.c +++ b/sys/dev/uart/uart_dev_ns8250.c @@ -31,6 +31,8 @@ __FBSDID("$FreeBSD$"); #include <sys/systm.h> #include <sys/bus.h> #include <sys/conf.h> +#include <sys/kernel.h> +#include <sys/sysctl.h> #include <machine/bus.h> #include <dev/uart/uart.h> @@ -845,6 +847,11 @@ ns8250_bus_setsig(struct uart_softc *sc, int sig) return (0); } +static int broken_txfifo = 0; +SYSCTL_INT(_hw, OID_AUTO, broken_txfifo, CTLFLAG_RW | CTLFLAG_TUN, + &broken_txfifo, 0, "UART FIFO has QEMU emulation bug"); +TUNABLE_INT("hw.broken_txfifo", &broken_txfifo); + static int ns8250_bus_transmit(struct uart_softc *sc) { @@ -862,7 +869,12 @@ ns8250_bus_transmit(struct uart_softc *sc) uart_setreg(bas, REG_DATA, sc->sc_txbuf[i]); uart_barrier(bas); } - sc->sc_txbusy = 1; + if (broken_txfifo) + ns8250_drain(bas, UART_DRAIN_TRANSMITTER); + else + sc->sc_txbusy = 1; uart_unlock(sc->sc_hwmtx); + if (broken_txfifo) + uart_sched_softih(sc, SER_INT_TXIDLE); return (0); } |
