Messages in this thread | | | Date | Fri, 2 Jan 2009 18:24:13 +0100 | From | Pavel Machek <> | Subject | Re: Power Management with rootfs on SDMMC. |
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Hi!
> > I am using linux-2.6.27. I am testing power management after > > booting out of a SD/MMC card. > > My root file system is on a SD card. > > > > I am issuing the following command to suspend > > > > $ echo -n mem > /sys/power/state > > What happens is, The kernel hangs and it does not come out of suspend. > > even after i press keypad/generate serial input data. > > > > Has anyone tried this before? > > > > Am i missing something here? > > I don't think you're missing much, and you're definitely not alone. > > There have been long threads on mobile phone and netbook related forums about issues > with seemingly "any slightly advanced use whatsoever" of partitions on SD cards. > > IMHO in this strongly increasingly netbook- and mobile phone-enabled world it's > a bloody shame that: ... > - installing a swap partition on an SD card and then resuming can easily > go as far as __even completely corrupting__ the entire SD card partitioning > plus first partition (corrupts first 1kB of the card: both table and partition) > People then immediately resort to a non-helpful "Don't Do This, Ever" reply > (using swap partition on SD and suspend, see http://dev.laptop.org/ticket/6532#comment:10), > but to this I'd say: > News Flash, if this can theoretically be made to work at all using software > (i.e. there are no VM-related _hard_ blockers to such an operation > of using swap itself on a non-fixed SD slot), then this should goddamn be made > to work practically on Linux, _somehow_, since on SSD netbooks this is > the most natural thing to do to avoid wear of the builtin device.
I'd like to help with this one... can you reproduce this?
> (or, slightly reworded: I think it's high time for some kernel God to buy a measly > netbook or some such instead of 16-core mainframes to get a feeling for the > amount of issues that one hits there)
I have one and yes, its full of problems; see my blog post about 'evil little cards'.
OTOH currently you can't safely use ext3 on flash card, so suspend problems seem little 'uninteresting' compared to that. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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