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* rtcwake doesn't reset wakealarm
@ 2012-09-11 11:11 Giacomo
  2012-09-12  9:52 ` Giacomo
  0 siblings, 1 reply; 8+ messages in thread
From: Giacomo @ 2012-09-11 11:11 UTC (permalink / raw)
  To: util-linux

Hi,

I recently upgraded to util-linux 2.22 and I noticed that powertop started
reporting about 50-60 wakeups per second caused by rtc (interrupt 8). 

I quickly found out that this happened when I used rtcwake to wake up the
machine, and that after the reboot /sys/class/rtc/rtc0/wakealarm was still set
to the scheduled wakeup time (now in the past). Resetting it to 0 with "echo 0 >
/sys/class/rtc/rtc0/wakealarm" made the interrupt stop.

After a quick investigation I discovered that this is caused by commit
1707576155daf644c5df3c1776b52fd297ff9318 ("rtcwake: only invoke RTC_AIE_ON/OFF
ioctls in pairs"): my system uses RTC_WKALM_SET so ioctl_aie_on stays false and
RTC_AIE_OFF doesn't get called.

I removed the check to revert to the previous behaviour and after my machine
rebooted /sys/class/rtc/rtc0/wakealarm was correctly (I suppose) set to 0, rtc
didn't fire regular interrupts anymore and there were apparently no negative
consequences.

Is this a bug or am I missing something?

Thanks,

Giacomo

PS. I'm not subscribed to the list so please cc me if you need other information.


^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2012-09-13 16:31 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-09-11 11:11 rtcwake doesn't reset wakealarm Giacomo
2012-09-12  9:52 ` Giacomo
2012-09-12 10:09   ` Karel Zak
2012-09-12 10:31     ` Karel Zak
2012-09-12 14:33       ` Giacomo
2012-09-12 17:33         ` Giacomo
2012-09-13 11:25           ` Karel Zak
2012-09-13 16:31       ` Paul Fox

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