Arch Linux

schlehmil

Member

Registered: 2010-10-01

Posts: 19

Computer wakes up after a few minutes

Since I upgraded my laptops kernel from version 2.6.37.5-1 to 2.6.38.2-1 I experience wake ups after I powered my laptop off. This happens after about 10 minutes. The only solution so far is to remove the battery or wait for the laptop to start itself and then press the power button for a longer time during the boot process to power off again. Maybe there is something with the rtc alarm that is unintentionally set during the shut down sequence? Unfortunately there is no setting in the BIOS to disable wake up from rtc clock (Thinkpad T410). Is someone experiencing the same issue?

Problem seems to be solved: (not solved)
As it turns out the problem has nothing to do with the kernel update but with the hardware clock. We had a clock change a few days ago because of summertime. Something must went terribly wrong because the hardware clock was set 10minutes off.

schlehmil@shiva:~$ cat /proc/driver/rtc 
rtc_time    : 10:26:55
rtc_date    : 2011-04-05
alrm_time    : 00:00:00
alrm_date    : 1970-01-01
alarm_IRQ    : no
alrm_pending    : no
24hr        : yes
periodic_IRQ    : no
update_IRQ    : no
HPET_emulated    : yes
BCD        : yes
DST_enable    : no
periodic_freq    : 1024
batt_status    : okay
schlehmil@shiva:~$ date
Tue Apr  5 10:36:47 CEST 2011

I resynced the hardware clock with system clock and now my computer does not wake up automatically after 10 minutes. Nonetheless I do not understand why a wrong hardware clock can trigger a rtc wakeup if no alarm time is specified.

Last edited by schlehmil (2011-04-07 09:29:19)

Spacenick

Member

From: Germany

Registered: 2010-04-02

Posts: 168

Re: Computer wakes up after a few minutes

I had this problem once or twice after upgrade but it's gone since. I've one confirmed case and one where I shut it down remotely to find it rebooted when I returned home.
I'm running a first intel Gen iMac

Last edited by Spacenick (2011-04-05 21:08:41)

schlehmil

Member

Registered: 2010-10-01

Posts: 19

Re: Computer wakes up after a few minutes

As it turns out the issue is still persistent. There is no difference if I shutdown via gnome or init 0 or shutdown -h now in the console. The time until the computer starts again varies between instantly and 10 minutes.

Leonid.I

Member

From: Aethyr

Registered: 2009-03-22

Posts: 999

Re: Computer wakes up after a few minutes

It looks like a hardware/bios related problem, because in your /proc/driver/rtc 'alarm_pending' is 'no'. To see if this is indeed rtc, why don't you set an alarm explicitly in rc.shutdown? Does the machine obey this new setting, or it gets randomly reset?

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