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yaml --- r: 79696 b: refs/heads/master c: 316da3b h: refs/heads/master v: v3
git-mirror · Jan 30, 2008 · 2896e06 · 2896e06
1 parent 1506c9b
commit 2896e06
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Showing 2 changed files with 10 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: df619e6bafeb8e129aba3173d384544d7fa6e3c2
+refs/heads/master: 316da3b3fc8efa9a5d2c99e0d449f01ff38c6aba
diff --git a/trunk/arch/x86/kernel/i8253.c b/trunk/arch/x86/kernel/i8253.c
@@ -197,7 +197,15 @@ static struct clocksource clocksource_pit = {
 
 static int __init init_pit_clocksource(void)
 {
-	if (num_possible_cpus() > 1) /* PIT does not scale! */
+	 /*
+	  * Several reasons not to register PIT as a clocksource:
+	  *
+	  * - On SMP PIT does not scale due to i8253_lock
+	  * - when HPET is enabled
+	  * - when local APIC timer is active (PIT is switched off)
+	  */
+	if (num_possible_cpus() > 1 || is_hpet_enabled() ||
+	    pit_clockevent.mode != CLOCK_EVT_MODE_PERIODIC)
 		return 0;
 
 	clocksource_pit.mult = clocksource_hz2mult(CLOCK_TICK_RATE, 20);