[PATCH 6/7] HPET-RTC: fix timer config register accesses

[Clemens Ladisch]

Make sure that the RTC timer is in non-periodic mode; some stupid BIOS
might have initialized it to periodic mode.

Furthermore, don't set the SETVAL bit in the config register.  This
wouldn't have any effect unless the timer was in period mode (which it
isn't), and then the actual timer frequency would be half that of the
desired one because incrementing the comparator in the interrupt
handler would be done after the hardware has already incremented it
itself.

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 21:56:38.000000000 +0200
+++ linux-2.6.13/arch/i386/kernel/time_hpet.c	2005-09-27 21:59:13.000000000 +0200
@@ -309,7 +309,8 @@ int hpet_rtc_timer_init(void)
 	local_irq_restore(flags);
 
 	cfg = hpet_readl(HPET_T1_CFG);
-	cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT;
+	cfg &= ~HPET_TN_PERIODIC;
+	cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
 	hpet_writel(cfg, HPET_T1_CFG);
 
 	return 1;
@@ -335,12 +336,6 @@ static void hpet_rtc_timer_reinit(void)
 	cnt = hpet_readl(HPET_T1_CMP);
 	cnt += hpet_tick*HZ/hpet_rtc_int_freq;
 	hpet_writel(cnt, HPET_T1_CMP);
-
-	cfg = hpet_readl(HPET_T1_CFG);
-	cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT;
-	hpet_writel(cfg, HPET_T1_CFG);
-
-	return;
 }
 
 /*
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 21:57:27.000000000 +0200
+++ linux-2.6.13/arch/x86_64/kernel/time.c	2005-09-27 21:59:13.000000000 +0200
@@ -1139,7 +1139,8 @@ int hpet_rtc_timer_init(void)
 	local_irq_restore(flags);
 
 	cfg = hpet_readl(HPET_T1_CFG);
-	cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT;
+	cfg &= ~HPET_TN_PERIODIC;
+	cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
 	hpet_writel(cfg, HPET_T1_CFG);
 
 	return 1;
@@ -1165,12 +1166,6 @@ static void hpet_rtc_timer_reinit(void)
 	cnt = hpet_readl(HPET_T1_CMP);
 	cnt += hpet_tick*HZ/hpet_rtc_int_freq;
 	hpet_writel(cnt, HPET_T1_CMP);
-
-	cfg = hpet_readl(HPET_T1_CFG);
-	cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT;
-	hpet_writel(cfg, HPET_T1_CFG);
-
-	return;
 }
 
 /*
-
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