From 1339cad36a69faf633824fea64a263b07318911b Mon Sep 17 00:00:00 2001
From: marcel <marcel@FreeBSD.org>
Date: Sat, 10 Jul 2004 22:42:22 +0000
Subject: [PATCH] MFi386: don't fake the time counter when the debugger is
 active. This breaks the fundamental property of DELAY(). Instead, avoid
 grabbing clock_lock when kdb_active is non-zero.

---
 sys/amd64/isa/clock.c | 32 ++++++++++++--------------------
 1 file changed, 12 insertions(+), 20 deletions(-)

diff --git a/sys/amd64/isa/clock.c b/sys/amd64/isa/clock.c
index cfcf0d38d0a6..c311a2a856f0 100644
--- a/sys/amd64/isa/clock.c
+++ b/sys/amd64/isa/clock.c
@@ -54,6 +54,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/bus.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
+#include <sys/kdb.h>
 #include <sys/proc.h>
 #include <sys/time.h>
 #include <sys/timetc.h>
@@ -292,18 +293,8 @@ DELAY(int n)
 	 * takes about 1.5 usec for each of the i/o's in getit().  The loop
 	 * takes about 6 usec on a 486/33 and 13 usec on a 386/20.  The
 	 * multiplications and divisions to scale the count take a while).
-	 *
-	 * However, if ddb is active then use a fake counter since reading
-	 * the i8254 counter involves acquiring a lock.  ddb must not go
-	 * locking for many reasons, but it calls here for at least atkbd
-	 * input.
 	 */
-#ifdef DDB
-	if (db_active)
-		prev_tick = 0;
-	else
-#endif
-		prev_tick = getit();
+	prev_tick = getit();
 	n -= 0;			/* XXX actually guess no initial overhead */
 	/*
 	 * Calculate (n * (timer_freq / 1e6)) without using floating point
@@ -330,13 +321,7 @@ DELAY(int n)
 			     / 1000000;
 
 	while (ticks_left > 0) {
-#ifdef DDB
-		if (db_active) {
-			inb(0x84);
-			tick = prev_tick + 1;
-		} else
-#endif
-			tick = getit();
+		tick = getit();
 #ifdef DELAYDEBUG
 		++getit_calls;
 #endif
@@ -381,10 +366,17 @@ sysbeep(int pitch, int period)
 			splx(x);
 			return (-1); /* XXX Should be EBUSY, but nobody cares anyway. */
 		}
-	mtx_lock_spin(&clock_lock);
+#ifdef KDB
+	if (!kdb_active)
+#endif
+		mtx_lock_spin(&clock_lock);
 	outb(TIMER_CNTR2, pitch);
 	outb(TIMER_CNTR2, (pitch>>8));
-	mtx_unlock_spin(&clock_lock);
+#ifdef KDB
+	if (!kdb_active)
+#endif
+		mtx_unlock_spin(&clock_lock);
+
 	if (!beeping) {
 		/* enable counter2 output to speaker */
 		outb(IO_PPI, inb(IO_PPI) | 3);