From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 25 Mar 2007 12:42:51 +0000 (+0200)
Subject: [PATCH] clocksource: Fix thinko in watchdog selection
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=948ac6d71cf868b431adb3139d8dfbd9c4e4a6ca;p=openwrt%2Fstaging%2Fblogic.git

[PATCH] clocksource: Fix thinko in watchdog selection

The watchdog implementation excludes low res / non continuous
clocksources from being selected as a watchdog reference
unintentionally.

Allow using jiffies/PIT as a watchdog reference as long as no better
clocksource is available. This is necessary to detect TSC breakage on
systems, which have no pmtimer/hpet.

The main goal of the initial patch (preventing to switch to highres/nohz
when no reliable fallback clocksource is available) is still guaranteed
by the checks in clocksource_watchdog().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 5b0e46b56fd0..fe5c7db24247 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -151,7 +151,8 @@ static void clocksource_check_watchdog(struct clocksource *cs)
 			watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
 			add_timer(&watchdog_timer);
 		}
-	} else if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) {
+	} else {
+		if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
 			cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
 
 		if (!watchdog || cs->rating > watchdog->rating) {