I have installed BetterBatteryStats and CPU SPY, because I noticed that I had a faster than normal battery consumption when the tab was left alone.

I made a 30 mins test Wifi OFF, Flight Mode On, where the 29 mins of them showed me l2_hsic under Kernel Wakelock -> Since Unplugged.

Does anyone know what causes this and how to prevent it ?

Thank you.

( I am running Stock ICS 4.0.4 rooted)

  • Do you have a Galaxy Note?
    – Flow
    Commented Aug 21, 2012 at 18:32
  • @Flow No, I am having Samsung Tab 10.1
    – EnexoOnoma
    Commented Aug 21, 2012 at 18:40
  • 4
    It's a known problem on the Galaxy Note. But a quick google search showed no solution.
    – Flow
    Commented Aug 21, 2012 at 20:09
  • @Flow So I guess we payed for flawed devices ?
    – EnexoOnoma
    Commented Aug 21, 2012 at 22:54
  • 1
    @Flow: Is there currently a manufacturer that regularly updates ~16 month old phones (the time difference between the Galaxy S release and the release of ICS)? Commented Dec 16, 2012 at 21:41

1 Answer 1


As Flow already pointed out in his comment to the question, that is a known bug. However, if you're affected, there's at least a kind of "ugly work-around", as described in the article How to solve battery issues after ICS update in your Galaxy Note. Their conclusion states:

Anyway, this is a kernel bug in ICS, we have to wait for new update. The solution for this is: shutdown your Note, peel off the back cover, remove the battery; hold the battery for more than one min, put the battery back, put back the back cover; start the phone. Then, everything goes back to normal. Reboot your phone will NOT solver this issue, at least for me.
Next time, when you encounter this issue again, try the procedure again.

They further write that, if you once encountered this bug and worked-around this way, it seems it is hard to hit the bug again -- so with some luck, you will only have to do this once.

And yes, I saw that article refers to the Galaxy Note. But talking about a kernel bug in ICS, and your tablet being from the same manufacturer, chances are pretty good this solution will apply to your tablet as well.

  • 1
    Just to add, newer versions of CM10-based ROMs don't seem to have this problem (it went away for me at least). Commented Dec 16, 2012 at 21:37

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