Re: 2.2.18/swsusp bugs

Pavel Machek (pavel@suse.cz)
Fri, 1 Mar 2002 10:59:07 +0100


Hi!

> >> Alright, but provided that trying to resume from a non-suspend swap
> >> doesn't crash anything...
>
> PM> Do you stop all user processes before doing resume, for example?
>
> (Different subject, hey?-). No, I don't. At the point I do (and recommend to)
> swapon is during early init processing. There are no user processes at that
> point. If they are, they disappear in thin air at that point...
>
> But I already gave up, I agree w/your method. But remember that people will
> boot resume=/bla even when they have no swap to resume from. Just a lilo thing,
> unavoidable.
>
> PM> But that might be problem at resume. Imagine uhci has buffers at
> PM> 0x12345678, but in image being resumed, /bin/bash is at 0x12345678. Then
> PM> you have a problem.
>
> Nope, that can't happen. uhci and bash had their pages neatly restored...
> Wait! Are you saying you start uhci/netdrivers/enable interrupts BEFORE
> resuming?? Nonono! Forbidden! Disk corruption, or your computer may
> explode!

But you were running uhci/netdrivers before resuming, too, right?

How I'm going to solve this is to introduce "stop" callback to all
device drivers. NOte: I have to enable DMA/interrupts BEFORE resuming
-- I acutally need interrupts for reading from disk, and I *may* need
uhci/DMA for resuming, too. (I actually did
resume=/dev/zip_drive_on_usb. Worked at one point.)

> PM> [swsusp list no longer works, doing cc to l-k.]
>
> So it seems. It didn't bounce yesterday, but didn't get a response. OTOH, l-k
> isn't too busy a place to discuss swsusp? How about the ACPI list?

Okay, if you prefer.
Pavel

-- 
Casualities in World Trade Center: ~3k dead inside the building,
cryptography in U.S.A. and free speech in Czech Republic.
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