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

[Tino Keitel <tino.keitel@gmx.de>]

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"