Messages in this thread | | | Date | Sun, 17 Jan 2010 13:26:18 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [suspend/resume] Re: userspace notification from module |
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On Sun, Jan 17, 2010 at 02:07:39PM +0100, Pavel Machek wrote: > AFAICT following message would be nice. > > 1) battery is critical, userspace please do something > > On zaurus and similar, you could add > > 2) oh and btw we had power failure so we suspended (or maybe -- so > hardware suspended itself -- rmk's examples and old apm systems); we > are now back and running > > notification... but... ideally those power failures should never > happen anyway, so... having this notification is in no way neccessary.
There's another consideration here: the more complex the emergency procedure, the higher the chance of _something_ causing it to fail, and if it does fail, the result is data loss.
In a properly running system, this isn't something that's going to get a lot of testing, so there's a higher chance that there will be bugs, so the simpler the solution, the better.
It's a bit like the kernel shutdown paths - because they don't get a lot of use, they don't get tested enough, and having discussed it with Arjan van de Ven, it's a known weakness. So we know that they're not that well tested - and the result is eg, 33-rc3 on shutdown results in an oops for me on x86.
You really don't want to oops or deadlock on "battery critically low".
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