Re: Software Suspend [was Re: APM "SuspendToDisk" implementation

Bas Vermeulen (asethman@mandate-inc.com)
Fri, 27 Nov 1998 19:28:39 -0500 (EST)


Sounds rather interesting, any pointers as to where I could find any
patches. I really hate seeing that bloody "Unknown Interrupt" message when
Suspend this laptop and having the thing croak. (BTW I had a 486 laptop
where this actually worked). At least if not doing are own suspend to
disk, we could probably get the drivers to be "bullet proof". And hey,
I'm sure we could have some other benefits to this.

Aaron
<asethman@mandate-inc.com>

On Thu, 26 Nov 1998, Gabor Kuti wrote:

> > I think the point is sometimes the IDE driver can't properly recover
> > in this situation. There are really two ways to properly fix suspend:
> >
> > 1. Device drivers can be "bullet proofed" to the point that they can
> > recover automatically from a complete loss of device state.
> >
> > 2. Drivers can be made APM-aware, so that they directly handle APM
> > suspend and resume notifications.
> >
> > I think both are desirable. Strange things happen and drivers should
> > be fault tolerant. This doesn't have to be horribly expensive... it
> > might just mean sanity checking status values in a few key places, and
> > having the ability to do a from-scratch initialization of a device if
> > all else fails. And even if drivers can blindly recover from a
> > suspend, eventually we won't be satisfied with spewing messages about
> > unresponsive devices whenever a system is resumed, and we'll want to
> > distinguish this situation from a genuine hardware problem.
> I'm working on a Software Suspend right now.
> Today I've had my first _real_ success when the saved state came back and
> worked without oops :)
> Still I have left fairly quantity of work but today it showed me that it
> is all possible [I started to lose my faith]
>
> I will need to make a register_suspend function which calls the registered
> drivers/etc by resuming so they can restore state [they are registered by
> boot]. I think this could be useful for APM suspend too. I did not get
> into it too deeply yet tough. [I'm happy that reloading works].
> [My program creates a filename called /suspend.img and saves there what
> could not be swapped out, so I don't waste a byte]. In case of any
> interest prototype should be here soon [I have other works to do :((]
>
> Ps: right now is is called CONFIG_MACHINE_SUSPEND. Should I rename it
> CONFIG_SOFTWARE_SUSPEND in order not to confuse with laptop's hw suspend?
>
>
> Seasons
> \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
> "One who has time to complain has time to submit patches." <chinese proverb>
> \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
>
>
>
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