diff --git a/sys/amd64/amd64/tsc.c b/sys/amd64/amd64/tsc.c
index 2676332d8e39..196d34ce75ca 100644
--- a/sys/amd64/amd64/tsc.c
+++ b/sys/amd64/amd64/tsc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.31 1995/01/19 22:05:27 ats Exp $
+ *	$Id: clock.c,v 1.32 1995/03/16 18:11:58 bde Exp $
  */
 
 /*
@@ -92,6 +92,7 @@
 
 int	adjkerntz = 0;		/* offset from CMOS clock */
 int	disable_rtc_set	= 0;	/* disable resettodr() if != 0 */
+u_int	idelayed;
 #ifdef I586_CPU
 int	pentium_mhz;
 #endif
@@ -124,6 +125,7 @@ void
 clkintr(struct clockframe frame)
 {
 	hardclock(&frame);
+	setdelayed();
 }
 #else
 void
@@ -132,15 +134,18 @@ clkintr(struct clockframe frame)
 	timer_func(&frame);
 	switch (timer0_state) {
 	case 0:
+		setdelayed();
 		break;
 	case 1:
 		if ((timer0_prescaler_count += timer0_max_count)
 		    >= hardclock_max_count) {
 			hardclock(&frame);
+			setdelayed();
 			timer0_prescaler_count -= hardclock_max_count;
 		}
 		break;
 	case 2:
+		setdelayed();
 		timer0_max_count = TIMER_DIV(new_rate);
 		timer0_overflow_threshold =
 			timer0_max_count - TIMER0_LATCH_COUNT;
@@ -157,6 +162,7 @@ clkintr(struct clockframe frame)
 		if ((timer0_prescaler_count += timer0_max_count)
 		    >= hardclock_max_count) {
 			hardclock(&frame);
+			setdelayed();
 			timer0_max_count = hardclock_max_count;
 			timer0_overflow_threshold =
 				timer0_max_count - TIMER0_LATCH_COUNT;
diff --git a/sys/amd64/isa/clock.c b/sys/amd64/isa/clock.c
index 2676332d8e39..196d34ce75ca 100644
--- a/sys/amd64/isa/clock.c
+++ b/sys/amd64/isa/clock.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.31 1995/01/19 22:05:27 ats Exp $
+ *	$Id: clock.c,v 1.32 1995/03/16 18:11:58 bde Exp $
  */
 
 /*
@@ -92,6 +92,7 @@
 
 int	adjkerntz = 0;		/* offset from CMOS clock */
 int	disable_rtc_set	= 0;	/* disable resettodr() if != 0 */
+u_int	idelayed;
 #ifdef I586_CPU
 int	pentium_mhz;
 #endif
@@ -124,6 +125,7 @@ void
 clkintr(struct clockframe frame)
 {
 	hardclock(&frame);
+	setdelayed();
 }
 #else
 void
@@ -132,15 +134,18 @@ clkintr(struct clockframe frame)
 	timer_func(&frame);
 	switch (timer0_state) {
 	case 0:
+		setdelayed();
 		break;
 	case 1:
 		if ((timer0_prescaler_count += timer0_max_count)
 		    >= hardclock_max_count) {
 			hardclock(&frame);
+			setdelayed();
 			timer0_prescaler_count -= hardclock_max_count;
 		}
 		break;
 	case 2:
+		setdelayed();
 		timer0_max_count = TIMER_DIV(new_rate);
 		timer0_overflow_threshold =
 			timer0_max_count - TIMER0_LATCH_COUNT;
@@ -157,6 +162,7 @@ clkintr(struct clockframe frame)
 		if ((timer0_prescaler_count += timer0_max_count)
 		    >= hardclock_max_count) {
 			hardclock(&frame);
+			setdelayed();
 			timer0_max_count = hardclock_max_count;
 			timer0_overflow_threshold =
 				timer0_max_count - TIMER0_LATCH_COUNT;
diff --git a/sys/i386/i386/tsc.c b/sys/i386/i386/tsc.c
index 2676332d8e39..196d34ce75ca 100644
--- a/sys/i386/i386/tsc.c
+++ b/sys/i386/i386/tsc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.31 1995/01/19 22:05:27 ats Exp $
+ *	$Id: clock.c,v 1.32 1995/03/16 18:11:58 bde Exp $
  */
 
 /*
@@ -92,6 +92,7 @@
 
 int	adjkerntz = 0;		/* offset from CMOS clock */
 int	disable_rtc_set	= 0;	/* disable resettodr() if != 0 */
+u_int	idelayed;
 #ifdef I586_CPU
 int	pentium_mhz;
 #endif
@@ -124,6 +125,7 @@ void
 clkintr(struct clockframe frame)
 {
 	hardclock(&frame);
+	setdelayed();
 }
 #else
 void
@@ -132,15 +134,18 @@ clkintr(struct clockframe frame)
 	timer_func(&frame);
 	switch (timer0_state) {
 	case 0:
+		setdelayed();
 		break;
 	case 1:
 		if ((timer0_prescaler_count += timer0_max_count)
 		    >= hardclock_max_count) {
 			hardclock(&frame);
+			setdelayed();
 			timer0_prescaler_count -= hardclock_max_count;
 		}
 		break;
 	case 2:
+		setdelayed();
 		timer0_max_count = TIMER_DIV(new_rate);
 		timer0_overflow_threshold =
 			timer0_max_count - TIMER0_LATCH_COUNT;
@@ -157,6 +162,7 @@ clkintr(struct clockframe frame)
 		if ((timer0_prescaler_count += timer0_max_count)
 		    >= hardclock_max_count) {
 			hardclock(&frame);
+			setdelayed();
 			timer0_max_count = hardclock_max_count;
 			timer0_overflow_threshold =
 				timer0_max_count - TIMER0_LATCH_COUNT;
diff --git a/sys/i386/include/spl.h b/sys/i386/include/spl.h
index 3ffc50fd1bbd..1db479fe5ddc 100644
--- a/sys/i386/include/spl.h
+++ b/sys/i386/include/spl.h
@@ -30,7 +30,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: spl.h,v 1.6 1994/12/30 12:42:15 bde Exp $
+ *	$Id: spl.h,v 1.7 1995/05/11 00:13:01 wollman Exp $
  */
 
 #ifndef _MACHINE_IPL_H_
@@ -74,6 +74,7 @@
 
 extern	unsigned bio_imask;	/* group of interrupts masked with splbio() */
 extern	unsigned cpl;		/* current priority level mask */
+extern	volatile unsigned idelayed;	/* interrupts to become pending */
 extern	volatile unsigned ipending;	/* active interrupts masked by cpl */
 extern	unsigned net_imask;	/* group of interrupts masked with splimp() */
 extern	unsigned stat_imask;	/* interrupts masked with splstatclock() */
@@ -85,11 +86,14 @@ extern	unsigned tty_imask;	/* group of interrupts masked with spltty() */
  * it is changed.  Pretending that ipending is a plain int happens to give
  * suitable atomic code for "ipending |= constant;".
  */
+#define	setdelayed()	(*(unsigned *)&ipending |= loadandclear(&idelayed))
 #define	setsoftast()	(*(unsigned *)&ipending |= SWI_AST_PENDING)
 #define	setsoftclock()	(*(unsigned *)&ipending |= SWI_CLOCK_PENDING)
 #define	setsoftnet()	(*(unsigned *)&ipending |= SWI_NET_PENDING)
 #define	setsofttty()	(*(unsigned *)&ipending |= SWI_TTY_PENDING)
 
+#define	schedsofttty()	(*(unsigned *)&idelayed |= SWI_TTY_PENDING)
+
 void	unpend_V __P((void));
 
 #ifdef __GNUC__
diff --git a/sys/i386/isa/clock.c b/sys/i386/isa/clock.c
index 2676332d8e39..196d34ce75ca 100644
--- a/sys/i386/isa/clock.c
+++ b/sys/i386/isa/clock.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.31 1995/01/19 22:05:27 ats Exp $
+ *	$Id: clock.c,v 1.32 1995/03/16 18:11:58 bde Exp $
  */
 
 /*
@@ -92,6 +92,7 @@
 
 int	adjkerntz = 0;		/* offset from CMOS clock */
 int	disable_rtc_set	= 0;	/* disable resettodr() if != 0 */
+u_int	idelayed;
 #ifdef I586_CPU
 int	pentium_mhz;
 #endif
@@ -124,6 +125,7 @@ void
 clkintr(struct clockframe frame)
 {
 	hardclock(&frame);
+	setdelayed();
 }
 #else
 void
@@ -132,15 +134,18 @@ clkintr(struct clockframe frame)
 	timer_func(&frame);
 	switch (timer0_state) {
 	case 0:
+		setdelayed();
 		break;
 	case 1:
 		if ((timer0_prescaler_count += timer0_max_count)
 		    >= hardclock_max_count) {
 			hardclock(&frame);
+			setdelayed();
 			timer0_prescaler_count -= hardclock_max_count;
 		}
 		break;
 	case 2:
+		setdelayed();
 		timer0_max_count = TIMER_DIV(new_rate);
 		timer0_overflow_threshold =
 			timer0_max_count - TIMER0_LATCH_COUNT;
@@ -157,6 +162,7 @@ clkintr(struct clockframe frame)
 		if ((timer0_prescaler_count += timer0_max_count)
 		    >= hardclock_max_count) {
 			hardclock(&frame);
+			setdelayed();
 			timer0_max_count = hardclock_max_count;
 			timer0_overflow_threshold =
 				timer0_max_count - TIMER0_LATCH_COUNT;
diff --git a/sys/isa/atrtc.c b/sys/isa/atrtc.c
index 2676332d8e39..196d34ce75ca 100644
--- a/sys/isa/atrtc.c
+++ b/sys/isa/atrtc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.31 1995/01/19 22:05:27 ats Exp $
+ *	$Id: clock.c,v 1.32 1995/03/16 18:11:58 bde Exp $
  */
 
 /*
@@ -92,6 +92,7 @@
 
 int	adjkerntz = 0;		/* offset from CMOS clock */
 int	disable_rtc_set	= 0;	/* disable resettodr() if != 0 */
+u_int	idelayed;
 #ifdef I586_CPU
 int	pentium_mhz;
 #endif
@@ -124,6 +125,7 @@ void
 clkintr(struct clockframe frame)
 {
 	hardclock(&frame);
+	setdelayed();
 }
 #else
 void
@@ -132,15 +134,18 @@ clkintr(struct clockframe frame)
 	timer_func(&frame);
 	switch (timer0_state) {
 	case 0:
+		setdelayed();
 		break;
 	case 1:
 		if ((timer0_prescaler_count += timer0_max_count)
 		    >= hardclock_max_count) {
 			hardclock(&frame);
+			setdelayed();
 			timer0_prescaler_count -= hardclock_max_count;
 		}
 		break;
 	case 2:
+		setdelayed();
 		timer0_max_count = TIMER_DIV(new_rate);
 		timer0_overflow_threshold =
 			timer0_max_count - TIMER0_LATCH_COUNT;
@@ -157,6 +162,7 @@ clkintr(struct clockframe frame)
 		if ((timer0_prescaler_count += timer0_max_count)
 		    >= hardclock_max_count) {
 			hardclock(&frame);
+			setdelayed();
 			timer0_max_count = hardclock_max_count;
 			timer0_overflow_threshold =
 				timer0_max_count - TIMER0_LATCH_COUNT;