acpi alarm is gone and rtc wakealarm does not work

[Chris Rouch]

I'm running FC6 on an ASUS A6U series laptop. I have been using
/proc/acpi/alarm to suspend it and resume at a particular time, so it
can be used as an alarm clock and pump radio 4 into the bedroom.

Over the weekend I updated to the latest kernel, 2.6.22. In this
kernel /proc/acpi/alarm is gone. Googling for it I found that it was
considered legacy and removed in this kernel, replaced by
/sys/class/rtc/rtc0/wakealarm, which uses a different format, but is
supposed to do the same job. Except it doesn't on my laptop.

What little documentation there is for this says that it should take
the seconds since the epoch (e.g the result of date -d "+10 minutes"
+%s). This is silently rejected.

I found a program called rtcwake posted on the lkml mailing list..
This has a test mode which works, i.e. it sets a value into wakealarm
and then continues after the alarm expires. The value set is much
larger than the  number of seconds. Someone else saw "a constant
difference of 869984896 seconds" on their system. My difference is
also constant, but different to this (sorry I didn't write it down and
the laptop is not with me).

rtcwake sets the wakealarm value and sets the hibernate state (mem,
disk or standby) but the machine never tries to wake up.

Does anyone have any suggestions to make this work again - using the
rtc or any other mechanism? For the time being I've rolled back to
2.6.20, but I'd like to be able to update to F8 and beyond eventually.

Thanks for any help.


Chris