PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback

PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback

[Mark Lord]

Fix month wrap issue with readback from /proc/acpi/alarm
This bug has been around *forever*.

$ echo '2008-12-01 10:36:20' > /proc/acpi/alarm
$ cat /proc/acpi/alarm
2008-11-01 10:36:20

Note how the readback above shows the month incorrectly.
But with this patch applied, it shows the correct month (12).

Patch applies/works on kernels 2.6.25.* through 2.6.27.*,
and probably on earlier kernels as well.

Probably best to queue it up for the next major cycle.

Signed-off-by: Mark Lord <mlord@pobox.com>

--- linux-2.6.25/drivers/acpi/sleep/proc.c	2008-06-09 14:27:19.000000000 -0400
+++ linux/drivers/acpi/sleep/proc.c	2008-11-30 18:08:31.000000000 -0500
@@ -84,12 +84,15 @@
 #define	HAVE_ACPI_LEGACY_ALARM
 #endif
 
+static u32 cmos_bcd_read(int offset, int rtc_control);
+
 #ifdef	HAVE_ACPI_LEGACY_ALARM
 
 static int acpi_system_alarm_seq_show(struct seq_file *seq, void *offset)
 {
 	u32 sec, min, hr;
 	u32 day, mo, yr, cent = 0;
+	u32 today = 0;
 	unsigned char rtc_control = 0;
 	unsigned long flags;
 
@@ -97,38 +100,32 @@
 
 	spin_lock_irqsave(&rtc_lock, flags);
 
-	sec = CMOS_READ(RTC_SECONDS_ALARM);
-	min = CMOS_READ(RTC_MINUTES_ALARM);
-	hr = CMOS_READ(RTC_HOURS_ALARM);
 	rtc_control = CMOS_READ(RTC_CONTROL);
+	sec = cmos_bcd_read(RTC_SECONDS_ALARM, rtc_control);
+	min = cmos_bcd_read(RTC_MINUTES_ALARM, rtc_control);
+	hr = cmos_bcd_read(RTC_HOURS_ALARM, rtc_control);
 
 	/* If we ever get an FACP with proper values... */
-	if (acpi_gbl_FADT.day_alarm)
+	if (acpi_gbl_FADT.day_alarm) {
 		/* ACPI spec: only low 6 its should be cared */
 		day = CMOS_READ(acpi_gbl_FADT.day_alarm) & 0x3F;
-	else
-		day = CMOS_READ(RTC_DAY_OF_MONTH);
+		if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+			BCD_TO_BIN(day);
+	} else
+		day = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control);
 	if (acpi_gbl_FADT.month_alarm)
-		mo = CMOS_READ(acpi_gbl_FADT.month_alarm);
-	else
-		mo = CMOS_READ(RTC_MONTH);
+		mo = cmos_bcd_read(acpi_gbl_FADT.month_alarm, rtc_control);
+	else {
+		mo = cmos_bcd_read(RTC_MONTH, rtc_control);
+		today = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control);
+	}
 	if (acpi_gbl_FADT.century)
-		cent = CMOS_READ(acpi_gbl_FADT.century);
+		cent = cmos_bcd_read(acpi_gbl_FADT.century, rtc_control);
 
-	yr = CMOS_READ(RTC_YEAR);
+	yr = cmos_bcd_read(RTC_YEAR, rtc_control);
 
 	spin_unlock_irqrestore(&rtc_lock, flags);
 
-	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
-		BCD_TO_BIN(sec);
-		BCD_TO_BIN(min);
-		BCD_TO_BIN(hr);
-		BCD_TO_BIN(day);
-		BCD_TO_BIN(mo);
-		BCD_TO_BIN(yr);
-		BCD_TO_BIN(cent);
-	}
-
 	/* we're trusting the FADT (see above) */
 	if (!acpi_gbl_FADT.century)
 		/* If we're not trusting the FADT, we should at least make it
@@ -153,6 +150,20 @@
 	else
 		yr += cent * 100;
 
+	/*
+	 * Show correct dates for alarms up to a month into the future.
+	 * This solves issues for nearly all situations with the common
+	 * 30-day alarm clocks in PC hardware.
+	 */
+	if (day < today) {
+		if (mo < 12) {
+			mo += 1;
+		} else {
+			mo = 1;
+			yr += 1;
+		}
+	}
+
 	seq_printf(seq, "%4.4u-", yr);
 	(mo > 12) ? seq_puts(seq, "**-") : seq_printf(seq, "%2.2u-", mo);
 	(day > 31) ? seq_puts(seq, "** ") : seq_printf(seq, "%2.2u ", day);

Re: PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback

[Mark Lord]

Mark Lord wrote:
> Fix month wrap issue with readback from /proc/acpi/alarm
> This bug has been around *forever*.
> 
> $ echo '2008-12-01 10:36:20' > /proc/acpi/alarm
> $ cat /proc/acpi/alarm
> 2008-11-01 10:36:20
> 
> Note how the readback above shows the month incorrectly.
> But with this patch applied, it shows the correct month (12).
..

I should add, that the above test requires that the alarm
be set for any day of the *next* month from the current month.
My MythTV box does a readback test any time it programs a wakeup,
and noticed the bug over this past weekend (2008-11-30).

> 
> Patch applies/works on kernels 2.6.25.* through 2.6.27.*,
> and probably on earlier kernels as well.
> 
> Probably best to queue it up for the next major cycle.
> 
> Signed-off-by: Mark Lord <mlord@pobox.com>
> 
> --- linux-2.6.25/drivers/acpi/sleep/proc.c    2008-06-09 
> 14:27:19.000000000 -0400
> +++ linux/drivers/acpi/sleep/proc.c    2008-11-30 18:08:31.000000000 -0500
> @@ -84,12 +84,15 @@
> #define    HAVE_ACPI_LEGACY_ALARM
> #endif
> 
> +static u32 cmos_bcd_read(int offset, int rtc_control);
> +
> #ifdef    HAVE_ACPI_LEGACY_ALARM
> 
> static int acpi_system_alarm_seq_show(struct seq_file *seq, void *offset)
> {
>     u32 sec, min, hr;
>     u32 day, mo, yr, cent = 0;
> +    u32 today = 0;
>     unsigned char rtc_control = 0;
>     unsigned long flags;
> 
> @@ -97,38 +100,32 @@
> 
>     spin_lock_irqsave(&rtc_lock, flags);
> 
> -    sec = CMOS_READ(RTC_SECONDS_ALARM);
> -    min = CMOS_READ(RTC_MINUTES_ALARM);
> -    hr = CMOS_READ(RTC_HOURS_ALARM);
>     rtc_control = CMOS_READ(RTC_CONTROL);
> +    sec = cmos_bcd_read(RTC_SECONDS_ALARM, rtc_control);
> +    min = cmos_bcd_read(RTC_MINUTES_ALARM, rtc_control);
> +    hr = cmos_bcd_read(RTC_HOURS_ALARM, rtc_control);
> 
>     /* If we ever get an FACP with proper values... */
> -    if (acpi_gbl_FADT.day_alarm)
> +    if (acpi_gbl_FADT.day_alarm) {
>         /* ACPI spec: only low 6 its should be cared */
>         day = CMOS_READ(acpi_gbl_FADT.day_alarm) & 0x3F;
> -    else
> -        day = CMOS_READ(RTC_DAY_OF_MONTH);
> +        if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
> +            BCD_TO_BIN(day);
> +    } else
> +        day = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control);
>     if (acpi_gbl_FADT.month_alarm)
> -        mo = CMOS_READ(acpi_gbl_FADT.month_alarm);
> -    else
> -        mo = CMOS_READ(RTC_MONTH);
> +        mo = cmos_bcd_read(acpi_gbl_FADT.month_alarm, rtc_control);
> +    else {
> +        mo = cmos_bcd_read(RTC_MONTH, rtc_control);
> +        today = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control);
> +    }
>     if (acpi_gbl_FADT.century)
> -        cent = CMOS_READ(acpi_gbl_FADT.century);
> +        cent = cmos_bcd_read(acpi_gbl_FADT.century, rtc_control);
> 
> -    yr = CMOS_READ(RTC_YEAR);
> +    yr = cmos_bcd_read(RTC_YEAR, rtc_control);
> 
>     spin_unlock_irqrestore(&rtc_lock, flags);
> 
> -    if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
> -        BCD_TO_BIN(sec);
> -        BCD_TO_BIN(min);
> -        BCD_TO_BIN(hr);
> -        BCD_TO_BIN(day);
> -        BCD_TO_BIN(mo);
> -        BCD_TO_BIN(yr);
> -        BCD_TO_BIN(cent);
> -    }
> -
>     /* we're trusting the FADT (see above) */
>     if (!acpi_gbl_FADT.century)
>         /* If we're not trusting the FADT, we should at least make it
> @@ -153,6 +150,20 @@
>     else
>         yr += cent * 100;
> 
> +    /*
> +     * Show correct dates for alarms up to a month into the future.
> +     * This solves issues for nearly all situations with the common
> +     * 30-day alarm clocks in PC hardware.
> +     */
> +    if (day < today) {
> +        if (mo < 12) {
> +            mo += 1;
> +        } else {
> +            mo = 1;
> +            yr += 1;
> +        }
> +    }
> +
>     seq_printf(seq, "%4.4u-", yr);
>     (mo > 12) ? seq_puts(seq, "**-") : seq_printf(seq, "%2.2u-", mo);
>     (day > 31) ? seq_puts(seq, "** ") : seq_printf(seq, "%2.2u ", day);

Re: PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback

[Len Brown]

On Mon, 1 Dec 2008, Mark Lord wrote:

> Fix month wrap issue with readback from /proc/acpi/alarm
> This bug has been around *forever*.
> 
> $ echo '2008-12-01 10:36:20' > /proc/acpi/alarm
> $ cat /proc/acpi/alarm
> 2008-11-01 10:36:20
> 
> Note how the readback above shows the month incorrectly.
> But with this patch applied, it shows the correct month (12).
> 
> Patch applies/works on kernels 2.6.25.* through 2.6.27.*,
> and probably on earlier kernels as well.

We've had some BCD_TO_BIN() changes here in 2.6.28 already,
does 2.6.28-rc still have this bug?

I'd check myself, but I don't have a /proc/acpi/alarm due to this:

#if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || 
!defined(CONFIG_X86)
/* use /sys/class/rtc/rtcX/wakealarm instead; it's not ACPI-specific */
#else
#define HAVE_ACPI_LEGACY_ALARM
#endif


thanks,
-Len

Re: PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback

[Mark Lord]

Len Brown wrote:
..
> We've had some BCD_TO_BIN() changes here in 2.6.28 already,
> does 2.6.28-rc still have this bug?
..

Yes, bug still there.  Here is a version of the patch for 2.6.28-rc6

---snip---

Fix month wrap issue with readback from /proc/acpi/alarm
This bug has been around *forever*.

$ echo '2008-12-01 10:36:20' > /proc/acpi/alarm
$ cat /proc/acpi/alarm
2008-11-01 10:36:20

Note how the readback above shows the month incorrectly.
But with this patch applied, it shows the correct month (12).

This patch applies/works on 2.6.28-rc6.
Probably best to queue it up for the next major cycle.

Signed-off-by: Mark Lord <mlord@pobox.com> 

--- linux/drivers/acpi/sleep/proc.c	2008-11-20 18:19:22.000000000 -0500
+++ linux-2.6.28-rc6/drivers/acpi/sleep/proc.c	2008-12-01 17:07:51.000000000 -0500
@@ -84,12 +84,15 @@
 #define	HAVE_ACPI_LEGACY_ALARM
 #endif
 
+static u32 cmos_bcd_read(int offset, int rtc_control);
+
 #ifdef	HAVE_ACPI_LEGACY_ALARM
 
 static int acpi_system_alarm_seq_show(struct seq_file *seq, void *offset)
 {
 	u32 sec, min, hr;
 	u32 day, mo, yr, cent = 0;
+	u32 today = 0;
 	unsigned char rtc_control = 0;
 	unsigned long flags;
 
@@ -97,38 +100,32 @@
 
 	spin_lock_irqsave(&rtc_lock, flags);
 
-	sec = CMOS_READ(RTC_SECONDS_ALARM);
-	min = CMOS_READ(RTC_MINUTES_ALARM);
-	hr = CMOS_READ(RTC_HOURS_ALARM);
 	rtc_control = CMOS_READ(RTC_CONTROL);
+	sec = cmos_bcd_read(RTC_SECONDS_ALARM, rtc_control);
+	min = cmos_bcd_read(RTC_MINUTES_ALARM, rtc_control);
+	hr = cmos_bcd_read(RTC_HOURS_ALARM, rtc_control);
 
 	/* If we ever get an FACP with proper values... */
-	if (acpi_gbl_FADT.day_alarm)
+	if (acpi_gbl_FADT.day_alarm) {
 		/* ACPI spec: only low 6 its should be cared */
 		day = CMOS_READ(acpi_gbl_FADT.day_alarm) & 0x3F;
-	else
-		day = CMOS_READ(RTC_DAY_OF_MONTH);
+		if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+			day = bcd2bin(day);
+	} else
+		day = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control);
 	if (acpi_gbl_FADT.month_alarm)
-		mo = CMOS_READ(acpi_gbl_FADT.month_alarm);
-	else
-		mo = CMOS_READ(RTC_MONTH);
+		mo = cmos_bcd_read(acpi_gbl_FADT.month_alarm, rtc_control);
+	else {
+		mo = cmos_bcd_read(RTC_MONTH, rtc_control);
+		today = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control);
+	}
 	if (acpi_gbl_FADT.century)
-		cent = CMOS_READ(acpi_gbl_FADT.century);
+		cent = cmos_bcd_read(acpi_gbl_FADT.century, rtc_control);
 
-	yr = CMOS_READ(RTC_YEAR);
+	yr = cmos_bcd_read(RTC_YEAR, rtc_control);
 
 	spin_unlock_irqrestore(&rtc_lock, flags);
 
-	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
-		sec = bcd2bin(sec);
-		min = bcd2bin(min);
-		hr = bcd2bin(hr);
-		day = bcd2bin(day);
-		mo = bcd2bin(mo);
-		yr = bcd2bin(yr);
-		cent = bcd2bin(cent);
-	}
-
 	/* we're trusting the FADT (see above) */
 	if (!acpi_gbl_FADT.century)
 		/* If we're not trusting the FADT, we should at least make it
@@ -153,6 +150,20 @@
 	else
 		yr += cent * 100;
 
+	/*
+	 * Show correct dates for alarms up to a month into the future.
+	 * This solves issues for nearly all situations with the common
+	 * 30-day alarm clocks in PC hardware.
+	 */
+	if (day < today) {
+		if (mo < 12) {
+			mo += 1;
+		} else {
+			mo = 1;
+			yr += 1;
+		}
+	}
+
 	seq_printf(seq, "%4.4u-", yr);
 	(mo > 12) ? seq_puts(seq, "**-") : seq_printf(seq, "%2.2u-", mo);
 	(day > 31) ? seq_puts(seq, "** ") : seq_printf(seq, "%2.2u ", day);

Re: PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback

[Mark Lord]

Len Brown wrote:
> I don't have a /proc/acpi/alarm due to this:
> 
> #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || 
> !defined(CONFIG_X86)
> /* use /sys/class/rtc/rtcX/wakealarm instead; it's not ACPI-specific */
> #else
> #define HAVE_ACPI_LEGACY_ALARM
> #endif
..

Yeah.. bit of a nuisance that.
I regularly apply this patch to my own kernels:

--- old/drivers/acpi/sleep/proc.c	2008-01-06 16:39:45.000000000 -0500
+++ linux/drivers/acpi/sleep/proc.c	2008-01-06 17:35:35.000000000 -0500
@@ -78,11 +78,11 @@
 }
 #endif				/* CONFIG_ACPI_PROCFS */
 
-#if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || !defined(CONFIG_X86)
+//#if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || !defined(CONFIG_X86)
 /* use /sys/class/rtc/rtcX/wakealarm instead; it's not ACPI-specific */
-#else
+//#else
 #define	HAVE_ACPI_LEGACY_ALARM
-#endif
+//#endif
 
 #ifdef	HAVE_ACPI_LEGACY_ALARM
 

Re: [rtc-linux] Re: PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback

[Alessandro Zummo]

On Mon, 01 Dec 2008 17:15:46 -0500
Mark Lord <lkml@rtr.ca> wrote:

> Yeah.. bit of a nuisance that.
> I regularly apply this patch to my own kernels:

 While it will certainly work, maybe it's time to switch
 to /sys/class/rtc/rtcX/wakealarm . 

-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Torino, Italy

  http://www.towertech.it

Re: PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback

[Tino Keitel]

On Mon, Dec 01, 2008 at 12:02:06 -0500, Mark Lord wrote:
> Mark Lord wrote:
>> Fix month wrap issue with readback from /proc/acpi/alarm
>> This bug has been around *forever*.
>>
>> $ echo '2008-12-01 10:36:20' > /proc/acpi/alarm
>> $ cat /proc/acpi/alarm
>> 2008-11-01 10:36:20
>>
>> Note how the readback above shows the month incorrectly.
>> But with this patch applied, it shows the correct month (12).
> ..
>
> I should add, that the above test requires that the alarm
> be set for any day of the *next* month from the current month.
> My MythTV box does a readback test any time it programs a wakeup,
> and noticed the bug over this past weekend (2008-11-30).

Why not just use the new RTC drivers and /sys/class/rtc/rtc0/wakealarm?
MythTV already provides seconds since epoch for the wakeup time, so you
can use this value without converting it:

$ cat /usr/local/bin/myth-setwaketime
#!/bin/sh

SYSFS_WAKE_FILE="/sys/class/rtc/rtc0/wakealarm"

echo -n "Wakeup time is "
date -d @$1

if ! test -w "$SYSFS_WAKE_FILE" ; then
	exit 1
fi

echo 0 > "$SYSFS_WAKE_FILE"
echo "$1" > "$SYSFS_WAKE_FILE"

Re: PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback

[Mark Lord]

Tino Keitel wrote:
> On Mon, Dec 01, 2008 at 12:02:06 -0500, Mark Lord wrote:
>> Mark Lord wrote:
>>> Fix month wrap issue with readback from /proc/acpi/alarm
>>> This bug has been around *forever*.
>>>
>>> $ echo '2008-12-01 10:36:20' > /proc/acpi/alarm
>>> $ cat /proc/acpi/alarm
>>> 2008-11-01 10:36:20
>>>
>>> Note how the readback above shows the month incorrectly.
>>> But with this patch applied, it shows the correct month (12).
>> ..
>>
>> I should add, that the above test requires that the alarm
>> be set for any day of the *next* month from the current month.
>> My MythTV box does a readback test any time it programs a wakeup,
>> and noticed the bug over this past weekend (2008-11-30).
> 
> Why not just use the new RTC drivers and /sys/class/rtc/rtc0/wakealarm?
..

That question has nothing to do with fixing the bug in
the /proc/acpi/alarm code.  The bug is still there whether
I personally use a different mechanism or not!  :)

But in answer to your question, the new RTC drivers *also* fail
for some other reason.  They did work up until the HPET integration
(back in 2.6.26 ?), but have not worked since.

My MythTV box always tries the new ones, and if the readback test
fails to agree with what was attempted, it then falls back to
the old yet more reliable /proc/acpi/alarm.

I haven't really had time to find the exact breakage point and patch it
in the new RTC code yet (I put about 10 hours into it back then,
with no useful result), but the old code does have a useful fix.

Thus this thread.

Cheers

Re: [rtc-linux] Re: PATCH: /proc/acpi/alarm: handle day-of-month wraparound on readback

[Mark Lord]

Alessandro Zummo wrote:
> On Mon, 01 Dec 2008 17:15:46 -0500
> Mark Lord <lkml@rtr.ca> wrote:
> 
>> Yeah.. bit of a nuisance that.
>> I regularly apply this patch to my own kernels:
> 
>  While it will certainly work, maybe it's time to switch
>  to /sys/class/rtc/rtcX/wakealarm . 
..

Perhaps, but doing so would still leave the but in /proc/acpi/alarm,
so we need to fix it regardless.

Cheers

[PATCH] /proc/acpi/alarm: handle day-of-month wraparound on readback

[Mark Lord]

(repost)

Fix month wrap issue with readback from /proc/acpi/alarm
This bug has been around *forever*.

  $ echo '2008-12-01 10:36:20' > /proc/acpi/alarm
  $ cat /proc/acpi/alarm
  2008-11-01 10:36:20

Note how the readback above shows the month incorrectly
when the alarm is set in the *next* calendar month.
But with this patch applied, it shows the correct month (12).

This patch applies/works on 2.6.28-rc6.
Probably best to queue it up for the next major cycle.

Signed-off-by: Mark Lord <mlord@pobox.com>

--- old/drivers/acpi/sleep/proc.c	2008-11-20 18:19:22.000000000 -0500
+++ rc6/drivers/acpi/sleep/proc.c	2008-12-01 17:07:51.000000000 -0500
@@ -84,12 +84,15 @@
 #define	HAVE_ACPI_LEGACY_ALARM
 #endif
 
+static u32 cmos_bcd_read(int offset, int rtc_control);
+
 #ifdef	HAVE_ACPI_LEGACY_ALARM
 
 static int acpi_system_alarm_seq_show(struct seq_file *seq, void *offset)
 {
 	u32 sec, min, hr;
 	u32 day, mo, yr, cent = 0;
+	u32 today = 0;
 	unsigned char rtc_control = 0;
 	unsigned long flags;
 
@@ -97,38 +100,32 @@
 
 	spin_lock_irqsave(&rtc_lock, flags);
 
-	sec = CMOS_READ(RTC_SECONDS_ALARM);
-	min = CMOS_READ(RTC_MINUTES_ALARM);
-	hr = CMOS_READ(RTC_HOURS_ALARM);
 	rtc_control = CMOS_READ(RTC_CONTROL);
+	sec = cmos_bcd_read(RTC_SECONDS_ALARM, rtc_control);
+	min = cmos_bcd_read(RTC_MINUTES_ALARM, rtc_control);
+	hr = cmos_bcd_read(RTC_HOURS_ALARM, rtc_control);
 
 	/* If we ever get an FACP with proper values... */
-	if (acpi_gbl_FADT.day_alarm)
+	if (acpi_gbl_FADT.day_alarm) {
 		/* ACPI spec: only low 6 its should be cared */
 		day = CMOS_READ(acpi_gbl_FADT.day_alarm) & 0x3F;
-	else
-		day = CMOS_READ(RTC_DAY_OF_MONTH);
+		if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+			day = bcd2bin(day);
+	} else
+		day = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control);
 	if (acpi_gbl_FADT.month_alarm)
-		mo = CMOS_READ(acpi_gbl_FADT.month_alarm);
-	else
-		mo = CMOS_READ(RTC_MONTH);
+		mo = cmos_bcd_read(acpi_gbl_FADT.month_alarm, rtc_control);
+	else {
+		mo = cmos_bcd_read(RTC_MONTH, rtc_control);
+		today = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control);
+	}
 	if (acpi_gbl_FADT.century)
-		cent = CMOS_READ(acpi_gbl_FADT.century);
+		cent = cmos_bcd_read(acpi_gbl_FADT.century, rtc_control);
 
-	yr = CMOS_READ(RTC_YEAR);
+	yr = cmos_bcd_read(RTC_YEAR, rtc_control);
 
 	spin_unlock_irqrestore(&rtc_lock, flags);
 
-	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
-		sec = bcd2bin(sec);
-		min = bcd2bin(min);
-		hr = bcd2bin(hr);
-		day = bcd2bin(day);
-		mo = bcd2bin(mo);
-		yr = bcd2bin(yr);
-		cent = bcd2bin(cent);
-	}
-
 	/* we're trusting the FADT (see above) */
 	if (!acpi_gbl_FADT.century)
 		/* If we're not trusting the FADT, we should at least make it
@@ -153,6 +150,20 @@
 	else
 		yr += cent * 100;
 
+	/*
+	 * Show correct dates for alarms up to a month into the future.
+	 * This solves issues for nearly all situations with the common
+	 * 30-day alarm clocks in PC hardware.
+	 */
+	if (day < today) {
+		if (mo < 12) {
+			mo += 1;
+		} else {
+			mo = 1;
+			yr += 1;
+		}
+	}
+
 	seq_printf(seq, "%4.4u-", yr);
 	(mo > 12) ? seq_puts(seq, "**-") : seq_printf(seq, "%2.2u-", mo);
 	(day > 31) ? seq_puts(seq, "** ") : seq_printf(seq, "%2.2u ", day);

Re: [PATCH] /proc/acpi/alarm: handle day-of-month wraparound on readback

[Len Brown]

> (repost)

thanks for the refresh, Mark.
applied to acpi-test.

--
Len Brown, Intel Open Source Technology Center