Apply a patch that has been lingering in my inbox for far too long:

On a soekris Net5501, if you do a watchdog -t 16, followed by a watchdog
-t 0 to disable the watchdog, and then after some time (16s) re-enable
the watchdog the box reboots immediatly. This prevents also to stop and
restart watchdogd(8).

This is because when you stop the watchdog, the timer is not stoped,
only the hard reset is disabled. So when the timer has elapsed, the C2
event of the timer is set.

But when the hard reset is re-enabled, the event is not cleared and the
box reboots.

The attached patch stops and resets the counter when the watchdog is
disabled and do not disable the hard reset of the timer (if the timer
has elapsed it's too late).

Submitted by:	 Patrick Lamaizière

1 files changed, 13 insertions, 4 deletions

diff --git a/sys/i386/i386/geode.c b/sys/i386/i386/geode.c
index 32ea8f0..86dc734 100644
--- a/sys/i386/i386/geode.c
+++ b/sys/i386/i386/geode.c
@@ -208,14 +208,11 @@ geode_watchdog(void *foo __unused, u_int cmd, int *error)
 static void
 cs5536_watchdog(void *foo __unused, u_int cmd, int *error)
 {
-	u_int u, p;
+	u_int u, p, s;
 	uint16_t a;
 	uint32_t m;
 
 	a = rdmsr(0x5140000d);
-	m = rdmsr(0x51400029);
-	m &= ~(1 << 24);
-	wrmsr(0x51400029, m);
 
 	u = cmd & WD_INTERVAL;
 	if (u >= 30 && u <= 44) {
@@ -228,12 +225,24 @@ cs5536_watchdog(void *foo __unused, u_int cmd, int *error)
 		/* reset counter */
 		outw(a + 4, 0);
 		/* Arm reset mechanism */
+		m = rdmsr(0x51400029);
 		m |= (1 << 24);
 		wrmsr(0x51400029, m);
 		/* Start counter */
 		outw(a + 6, 0x8000);
 
 		*error = 0;
+	} else {
+		/* 
+		 * MFGPT_SETUP is write-once
+		 * Check if the counter has been setup
+		 */
+		s = inw(a + 6);
+		if (s & (1 << 12)) {
+			/* Stop and reset counter */
+			outw(a + 6, 0);
+			outw(a + 4, 0);
+		}
 	}
 }