linux-kernel - [PATCH]ACPI: Fix CMOS time error after waking up by /proc/acpi/alarm

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Date:	Thu, 19 Jun 2008 21:52:02 +0800
From:	"Chen, Huacai" <huacai.chen@...el.com>
To:	<linux-acpi@...r.kernel.org>,
	<linux-pm@...ts.linux-foundation.org>, <lenb@...nel.org>
Cc:	<linux-kernel@...r.kernel.org>
Subject: [PATCH]ACPI: Fix CMOS time error after waking up by /proc/acpi/alarm

From: Huacai Chen <huacai.chen@...el.com>

When writing /proc/acpi/alarm to wakeup up in adjust mode, this patch
read the "century" filed and add it to the "year" field before writing.
This avoids the CMOS time error (2000 years decrement) after waking up.

Signed-off-by: Huacai Chen <huacai.chen@...el.com>
---
diff --git a/drivers/acpi/sleep/proc.c b/drivers/acpi/sleep/proc.c
index 224c57c..2a85783 100644
--- a/drivers/acpi/sleep/proc.c
+++ b/drivers/acpi/sleep/proc.c
@@ -315,8 +315,11 @@ acpi_system_write_alarm(struct file *file,
 		cmos_bcd_write(day, acpi_gbl_FADT.day_alarm,
rtc_control);
 	if (acpi_gbl_FADT.month_alarm)
 		cmos_bcd_write(mo, acpi_gbl_FADT.month_alarm,
rtc_control);
-	if (acpi_gbl_FADT.century)
+	if (acpi_gbl_FADT.century){
+		if (adjust) 
+			yr += cmos_bcd_read(acpi_gbl_FADT.century,
rtc_control) * 100;
 		cmos_bcd_write(yr / 100, acpi_gbl_FADT.century,
rtc_control);
+	}
 	/* enable the rtc alarm interrupt */
 	rtc_control |= RTC_AIE;
 	CMOS_WRITE(rtc_control, RTC_CONTROL);
---
--
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