Merged from sys/dev/sio/sio.c revisions 1.354 and 1.358.

1 files changed, 12 insertions, 3 deletions

diff --git a/sys/pc98/cbus/sio.c b/sys/pc98/cbus/sio.c
index dcf0fa3b9fb6..e90704d9fe2a 100644
--- a/sys/pc98/cbus/sio.c
+++ b/sys/pc98/cbus/sio.c
@@ -3308,9 +3308,14 @@ comparam(tp, t)
 		 * latencies are reasonable for humans.  Serial comms
 		 * protocols shouldn't expect anything better since modem
 		 * latencies are larger.
+		 *
+		 * We have to set the FIFO trigger point such that we
+		 * don't overflow it accidently if a serial interrupt
+		 * is delayed.  At high speeds, FIFO_RX_HIGH does not
+		 * leave enough slots free.
 		 */
 		com->fifo_image = t->c_ospeed <= 4800
-				  ? FIFO_ENABLE : FIFO_ENABLE | FIFO_RX_HIGH;
+				  ? FIFO_ENABLE : FIFO_ENABLE | FIFO_RX_MEDH;
 #ifdef COM_ESP
 		/*
 		 * The Hayes ESP card needs the fifo DMA mode bit set
@@ -4375,6 +4380,7 @@ siocnputc(dev, c)
 	dev_t	dev;
 	int	c;
 {
+	int	need_unlock;
 	int	s;
 	struct siocnstate	sp;
 	Port_t	iobase;
@@ -4384,13 +4390,16 @@ siocnputc(dev, c)
 	else
 		iobase = siocniobase;
 	s = spltty();
-	if (sio_inited)
+	need_unlock = 0;
+	if (sio_inited == 2 && !mtx_owned(&sio_lock)) {
 		mtx_lock_spin(&sio_lock);
+		need_unlock = 1;
+	}
 	siocnopen(&sp, iobase, comdefaultrate);
 	siocntxwait(iobase);
 	outb(iobase + com_data, c);
 	siocnclose(&sp, iobase);
-	if (sio_inited)
+	if (need_unlock)
 		mtx_unlock_spin(&sio_lock);
 	splx(s);
 }