Monday, June 02, 2008

ACPI alarm and openSUSE 11.0

Tested the ACPI Alarm (rtcwake) function in openSUSE 11.0. A very important feature for a media center.

It worked in openSUSE 10.2 but was disabled in openSUSE 10.3 due to issues. So my production media center is still running good old openSUSE 10.2.

I failed my first tests with openSUSE 11.0.
The /sys/class/rtc/rtc0/wakealarm file seems to stay empty when I write a time to it.
Could be because of the old/crappy bios. Need to test with some descent hardware.

If you got this working with openSUSE 11.0, please drop me a line.

If you got some free cycles and would like to test this:

Howto test:

This command should set your machine to wake in 5 minutes:
echo "+00-00-00 00:05:00" > /sys/class/rtc/rtc0/wakealarm

Check if the file is changed:
cat /sys/class/rtc/rtc0/wakealarm

Is there anything in the file?

Put SYSTOHC="no" in /etc/sysconfig/clock so that the bios clock is not touched when you shutdown.

Does it wakeup?


Anonymous said...

Did you find a way to make this work?
I agree this is a key feature for a "green" media center...
Great job, BTW!

Anonymous said...

Moosy, I've managed to get this working. I had a similar problem as you in that I couldn't echo anything to wakeupalarm.

I tried the rtcwakeup command but that didn't work either.

Finally tried this:

echo 0 > /sys/class/rtc/rtc0/wakealarm
echo `date '+%s' -d '+ 5 minutes'` > /sys/class/rtc/rtc0/wakealarm


and it worked. I don't know why though.