From 6354f6714f8e25ed74f8879e938aa374c6a6216a Mon Sep 17 00:00:00 2001
From: ariff <ariff@FreeBSD.org>
Date: Wed, 11 Jul 2007 14:27:45 +0000
Subject: [PATCH] Protect against divide by zero while calculating bus speed
 due to possible broken kernel timecounter.

Reported/Tested by:	silby
Approved by:		re (hrs)
MFC after:		1 day
---
 sys/dev/sound/pci/ich.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sys/dev/sound/pci/ich.c b/sys/dev/sound/pci/ich.c
index cebf0b6cf032..64e2eec38986 100644
--- a/sys/dev/sound/pci/ich.c
+++ b/sys/dev/sound/pci/ich.c
@@ -783,7 +783,11 @@ ich_calibrate(void *arg)
 		return;
 	}
 
-	actual_48k_rate = ((uint64_t)ch->blksz * 250000) / wait_us;
+	/* Just in case the timecounter screwed. It is possible, really. */
+	if (wait_us > 0)
+		actual_48k_rate = ((uint64_t)ch->blksz * 250000) / wait_us;
+	else
+		actual_48k_rate = 48000;
 
 	if (actual_48k_rate < 47500 || actual_48k_rate > 48500) {
 		sc->ac97rate = actual_48k_rate;