Re: suspend2 merge (was Re: [Suspend2-devel] Re: CFS and suspend2:hang in atomic copy)

From: Adrian Bunk
Date: Wed Apr 25 2007 - 11:18:33 EST

On Wed, Apr 25, 2007 at 07:23:50AM +0000, Pavel Machek wrote:
> Hi!
> > This is why there's a lot to be said for
> >
> > echo mem > /sys/power/state
> >
> > and being able to follow the path through _one_ object (the kernel) over
> > trying to figure out the interaction between many different parts with
> > different versions.
> The 'promise' is 'if you can get echo disk > /sys/power/state working,
> uswsusp will work. too'. IOW it should be ok to debug the in-kernel
> parts, only.
> Even I am running in-kernel swsusp, but my managers were pretty clear
> they want graphical progress bar hiding all the 'ugly' swsusp
> messages... and in the end the same uswsusp enables compression, too.
> > I absolutely detest all suspend-to-disk crap. Quite frankly, I hate the
> > whole thing. I think they've _all_ caused problems for the "true" suspend
> > (suspend-to-ram), and the last thing I want to see is three or four
> Well, it is a bit more complex than that.
> suspend-to-disk is a workaround for
> 'suspend-to-ram eats too much power' (plus some details like
> being able to replace battery).

Why does everyone think suspend-to-disk was a laptop-only thing?

My personal usage of suspend-to-disk is for turning the computer off in
the evening and getting the complete FVWM with all programs running,
open browser tabs,... back the next morning.

All I need for suspending is:
- echo "disk" > /sys/power/state

All I need for getting a running and usable system back is:
- turn on the power at the socket my computer is connected at
- swapoff -a; swapon -a [1]
- wait a bit until the above commands finished

That's much more convenient than a cold boot.

And it's working with a plain 2.6.16 kernel and zero userspace support.

> Pavel


[1] required step: working with 1 or 2 GB swapped out is horrible


"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

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