Hi!
Sorry for long delay. I got rtc wakeup to work... once per boot. On
2.6.24-rc3.
> > > root@amd:/sys/class/rtc/rtc0# ls -al wakealarm
> > > -rw-r--r-- 1 root root 0 Sep 20 12:30 wakealarm
> > > root@amd:/sys/class/rtc/rtc0# cat wakealarm
> > > root@amd:/sys/class/rtc/rtc0# cat wakealarm
>
> The alarm isn't set; so no value gets displayed.
>
>
> > > root@amd:/sys/class/rtc/rtc0#
> > >
> > >
> > > ...standard PC with reasonably recent kernel...
>
> Yeah, well a "standard PC" is chock full of fairly bizarrely
> glitchey hardware. Clocks and timers have more than their
> fair share, or x86_64 NOHZ support would be merged by now!
Oops. Ok, this is thinkpad x60, if that helps.
> > root@amd:/sys/class/rtc/rtc0# cat wakealarm
> > 2051629528
> > root@amd:/sys/class/rtc/rtc0# date +%s
> > 1190285030
>
> OK, in that situation you've definitely got some buglike behavior.
> My question is: how to fix it?
>
> The problem is that the RTC is reporting an alarm value with some
> fields flagged as "wildcard" -- e.g. day/month/year "out of range"
> so the hardware ignores those fields. This is very common on PC
> based RTCs, and much less common on embedded systems. (Which for
> some reason don't tend to cheap out on full date specs like PCs.)
I see... so situation is not nice :-(.
> I'm not sure which fix would be best; maybe Alessandro has an
> opinion.
Alessandro?
> Better might be
>
> echo $(( $(cat since_epoch) + 20 )) > wakealarm
>
> which has no timezone offset issues.
Good. that actually works.
> > root@amd:/sys/class/rtc/rtc0# cat wakealarm
> > root@amd:/sys/class/rtc/rtc0#
> >
> > Also, is there some documentation for wakealarm?
>
> "git show 3925a5ce44330767f7f0de5c58c6a797009f0f75" has some.
Thanks. Will put it into Doc*/rtc.txt.
> Are you sure it's not working? Other than the two issues I noted
> above -- borkage w.r.t. ACPI (which wasn't necessarily shown in your
> scripts above), and with wildcarding -- it looked to be correct.
It seems to be working now, not sure what changed.
rtc-sysfs.c: why this?
if (alarm > now) {
/* Avoid accidentally clobbering active alarms; we
can't
* entirely prevent that here, without even the
minimal
* locking from the /dev/rtcN api.
*/
retval = rtc_read_alarm(rtc, &alm);
if (retval < 0)
return retval;
if (alm.enabled)
return -EBUSY;
alm.enabled = 1;
People should not be "accidentally" writing to sysfs files...
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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