Re: [PATCH] PM / hibernate: Introduce snapshot test mode for hibernation

[Chen Yu]

Hi Pavel,
thanks for your reply,

On 2016å07æ13æ 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.
And here's a revised version of v2, which introduced a new test mode
in pm_test, thus users do not need to run a manual resume.
https://patchwork.kernel.org/patch/9226837/
> 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?
> I guess updating documentation would be welcome from my side,
> otherwise it should be ok.
OK, I'll  update the documents.
> Acked-by: Pavel Machek <pavel@xxxxxx>
thanks.
> Best regards,
> 								Pavel