3 files changed, 32 insertions(+), 1 deletions(-)

M port/devns16552.c
M port/portfns.h
M port/qio.c

@@ 830,6 830,10 @@ ns16552ctl(Uart *p, char *cmd)
 	case 'd':
 		ns16552dtr(p, n);
 		break;
+	case 'f':
+	case 'F':
+		qflush(p->oq);
+		break;
 	case 'H':
 	case 'h':
 		qhangup(p->iq);

@@ 192,6 192,7 @@ ulong		pwait(Waitmsg*);
 int		qcanread(Queue*);
 void		qclose(Queue*);
 int		qconsume(Queue*, void*, int);
+void		qflush(Queue*);
 void		qhangup(Queue*);
 void		qinit(void);
 int		qlen(Queue*);

@@ 609,6 609,7 @@ qclose(Queue *q)
 	bfirst = q->bfirst;
 	q->bfirst = 0;
 	q->len = 0;
+	q->noblock = 0;
 	iunlock(q);
 
 	/* free queued blocks */


@@ 649,7 650,6 @@ qreopen(Queue *q)
 	q->state &= ~Qclosed;
 	q->state |= Qstarve;
 	q->eof = 0;
-	q->noblock = 0;
 	q->limit = q->inilim;
 }
 


@@ 702,3 702,29 @@ qnoblock(Queue *q, int onoff)
 {
 	q->noblock = onoff;
 }
+
+/*
+ *  flush the output queue
+ */
+void
+qflush(Queue *q)
+{
+	Block *b, *bfirst;
+
+	/* mark it */
+	ilock(q);
+	bfirst = q->bfirst;
+	q->bfirst = 0;
+	q->len = 0;
+	iunlock(q);
+
+	/* free queued blocks */
+	while(bfirst){
+		b = bfirst->next;
+		freeb(bfirst);
+		bfirst = b;
+	}
+
+	/* wake up readers/writers */
+	wakeup(&q->wr);
+}