[PATCH 5/7] HPET-RTC: disable interrupt when no longer needed

[Clemens Ladisch]

When the emulated RTC interrupt is no longer needed, we better disable
it; otherwise, we get a spurious interrupt whenever the timer has
rolled over and reaches the same comparator value.

Having a superfluous interrupt every five minutes doesn't hurt much,
but it's bad style anyway.  ;-)

Signed-off-by: Clemens Ladisch <clemens@xxxxxxxxxx>

Index: linux-2.6.13/arch/i386/kernel/time_hpet.c
===================================================================
--- linux-2.6.13.orig/arch/i386/kernel/time_hpet.c	2005-09-27 21:54:12.000000000 +0200
+++ linux-2.6.13/arch/i386/kernel/time_hpet.c	2005-09-27 21:56:38.000000000 +0200
@@ -319,8 +319,12 @@ static void hpet_rtc_timer_reinit(void)
 {
 	unsigned int cfg, cnt;
 
-	if (!(PIE_on | AIE_on | UIE_on))
+	if (unlikely(!(PIE_on | AIE_on | UIE_on))) {
+		cfg = hpet_readl(HPET_T1_CFG);
+		cfg &= ~HPET_TN_ENABLE;
+		hpet_writel(cfg, HPET_T1_CFG);
 		return;
+	}
 
 	if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ))
 		hpet_rtc_int_freq = PIE_freq;
Index: linux-2.6.13/arch/x86_64/kernel/time.c
===================================================================
--- linux-2.6.13.orig/arch/x86_64/kernel/time.c	2005-09-27 21:54:12.000000000 +0200
+++ linux-2.6.13/arch/x86_64/kernel/time.c	2005-09-27 21:57:27.000000000 +0200
@@ -1149,8 +1149,12 @@ static void hpet_rtc_timer_reinit(void)
 {
 	unsigned int cfg, cnt;
 
-	if (!(PIE_on | AIE_on | UIE_on))
+	if (unlikely(!(PIE_on | AIE_on | UIE_on))) {
+		cfg = hpet_readl(HPET_T1_CFG);
+		cfg &= ~HPET_TN_ENABLE;
+		hpet_writel(cfg, HPET_T1_CFG);
 		return;
+	}
 
 	if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ))
 		hpet_rtc_int_freq = PIE_freq;
-
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