Messages in this thread | | | Date | Wed, 09 Jun 2010 10:07:20 +0100 | From | Alan Jenkins <> | Subject | Re: Regression: BUG when battery is removed before resuming from hibernation |
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Rafael J. Wysocki wrote: > On Tuesday 08 June 2010, Alan Jenkins wrote: > >> I found this bug 2.6.34 on my Asus EeePC 701 (x86_32 arch). It didn't >> happen to me before, when I was running nearly-2.6.33 or 2.6.32-release. >> >> I used git-bisect, but unfortunately the result isn't very helpful. My >> next step will be to try to narrowing down the culprits by disabling >> individual CONFIG options. Here are my results so far, in case anyone >> is interested. >> >> >> == Steps to reproduce == >> >> I) Boot off mains power, with battery removed. Login to KDE4 session, >> with Konsole as the only running application. >> II) Run "sudo pm-hibernate" >> >> 1. When the system switches to text mode (a.k.a the console), >> immediately insert the battery. >> 2. Once the system has fully hibernated, remove the battery. >> 3. Press the power button to resume. The backtrace below is generated >> during resume. >> > > You're not supposed to be doing that. > > Rafael >
I take it you mean "don't plug devices in during hibernation; you'll run out of memory, Bad Things will happen, and you can expect resume to fail". Pity. It wasn't an artificial test case, just an unusual usage pattern of mine[1].
I guess it wouldn't be guaranteed safe even if I was plugging the device in first. The battery connection could take a few seconds to stabilize, and there's software equivalents in things like the usb-storage delay.
I can't complain about safety margins; other people might want to do similar things with an entire docking station...
Any chance of a big screaming warning? IIRC there's one global flag to fail userspace call-outs while userspace is frozen. Would it be acceptable to document this in code & behaviour by aborting the hibernation on hot-plug? (hot-*un*plug would presumably be allowed).
Alan
[1] I do this for conservation. I'm told batteries last longer if I don't use them & let them get warm. I put the battery in for hibernation so I can remove mains power without waiting. I start hibernation first, because in practice you have to have the screen closed in order to plug or unplug the battery.
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