2008-06-19 13:52:39

by Chen, Huacai

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

From: Huacai Chen <[email protected]>

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 <[email protected]>
---
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);
---

2008-06-23 09:10:12

by Pavel Machek

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

On Thu 2008-06-19 21:52:02, Chen, Huacai wrote:
> From: Huacai Chen <[email protected]>
>
> 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 <[email protected]>

Probably word-wrapped,

> ---
> 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){

and you definitely want ") {" here.

It probably should go to Len and RTC maintainers?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html