Hi! > > > The outcome: I'm no more enthusiastic about enabling this in Red Hat > > > kernels than I ever was before. It seems to have real issues with LVM > > > setups (which is default on Red Hat/Fedora installs these days). > > > After convincing it where to suspend/resume from by feeding it > > > the major/minor of my swap partition, it did actually seem > > > to suspend. And resume (though it did spew lots of 'sleeping whilst > > > atomic warnings, but thats trivial compared to whats coming up > > > next). > > > > I do not know much about LVM. How exactly did you resume= command line > > look like? You were not resuming from initrd, right? > > Indeed, this was very likely the problem. Doing a resume if I had > any partition mounted was *bad* news. We implemented the necessary > bits in our initrd today to detect resume partitions, and erm.. resume them. > So far so good, no repeats of the corruption I saw. Aha, good. > As of tomorrow rawhide kernels (for the unenlightened: these will > eventually be FC5) will have software suspend support. > > Our initial experiments with it have been fairly positive, though as > expected there are a number of drivers that don't survive the resume > correctly. http://www.livejournal.com/users/kernelslacker/22975.html I see, having ext3 (or anything else) mounted when doing resume is going to kill you data, fast. I thought warning in docs was good enough :-). Anyway, if you want to make this idiot-proof, I think the preferred way is to kill suspend signature during the boot [it is must-have for failsafe boot, so you can recover system if resume crashes it]. That way user can echo whatever to resume, but having no signature means he is not going to cause big damage. [Actually there are more easy ways to kill some data. Suspend, do normal boot next time, change something on disk, reboot and make it resume. Bye-bye data.] Okay, I realized I had too many warnings in there, and some things (like no driver support) is not _that_ dangerous, while resuming with filesystems mounted clearly is. I'll probably change the warning to: * BIG FAT WARNING ********************************************************* * * If you touch anything on disk between suspend and resume... * ...kiss your data goodbye. * * If you do resume from initrd after your filesystems are mounted... * ...bye bye root partition. * [this is actually same case as above] * * If you have unsupported (*) devices using DMA, you may have some * problems. If your disk driver does not support suspend... (IDE does), * it may cause some problems, too. If you change kernel command line * between suspend and resume, it may do something wrong. If you change * your hardware while system is suspended... well, it was not good idea; * but it wil probably only crash. * * (*) suspend/resume support is needed to make it safe. Pavel -- if you have sharp zaurus hardware you don't need... you know my address
