Messages in this thread | | | From | Chen Yu <> | Subject | Re: [PATCH] PM / hibernate: Introduce snapshot test mode for hibernation | Date | Wed, 13 Jul 2016 18:39:44 +0800 |
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On 2016年07月13日 18:21, Pavel Machek wrote: > Hi! > >> On 2016???07???13??? 17:50, Pavel Machek wrote: >>> On Thu 2016-07-07 14:40:58, Chen Yu wrote: >>>> This mode is to verify if the snapshot data written to >>>> swap device can be successfully restored to memory. It >>>> is useful to ease the debugging process on hibernation, >>>> since this mode can not only bypass the BIOSen/bootloader, >>>> but also the system re-initialization. >>>> >>>> For example: >>>> $ sudo echo snapshot > /sys/power/disk >>>> $ sudo echo disk > /sys/power/state >>>> >>>> /* manual resume.*/ >>>> $ sudo echo 8:3 > /sys/power/resume >>> Your examples will not work, will they? >> It works on my platform, although I did not tested it for too many >> rounds. > Please check again: > > sudo echo disk > /sys/power/state > -bash: /sys/power/state: Permission denied > > ...because bash does the open, not echo. Sorry, my bad, I logined as root:P I'll rewrite the commit log. >>> This is also quite tricky/dangerous. If you do this with filesystems >>> mounted R/W, it is "good bye, filesystems". >> Ah, yes, this is quite tricky, maybe we can use this option as a >> debug method, >> for example, boot with rootfs = initrd, without mounting any disks, >> and then swapon the swap device, and do a testing. This should be safer? > Yeah, that's the way. Read-only root is other option. > >>> I guess updating documentation would be welcome from my side, >>> otherwise it should be ok. >> OK, I'll update the documents. > Just add fat warning into the documentation. OK. > Thanks, > Pavel
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