Stefan Seyfried wrote:
Hi,
On Sat, May 26, 2007 at 06:42:37PM -0400, Bill Davidsen wrote:
I was testing susp2disk in 2.6.21.1 under FC6, to support reliable computing
environment (RCE) needs. The idea is that if power fails, after some short
time on UPS the system does susp2disk with a time set, and boots back every
so often to see if power is stable.
Interesting use case.
No, I don't want susp2mem until I debug it, console come up in useless mode,
console as kalidescope is not what I need.
You probably need to reset the video mode. Try the s2ram workaround,
specifically "-m".
Anyway, I pulled the plug on the UPS, and the system shut down. But when it
powered up, it booted the default kernel rather than the test kernel, decided
that it couldn't resume, and then did a cold boot.
I can bypass this by making the debug kernel the default, but WHY? Is the
kernel not saved such that any kernel can be rolled back into memory and run?
The Kernel does nothing to the bootloader during suspend. The kernel does not
even know that you are using a bootloader and how it might be configured.
What I really expected is that what I was running would be save, and
resume would restore what I was running and then jump back to where that
suspended itself. Without having to address the issue of booting the
"right" kernel, but having any functional kernel which was booted then
restore whar was originally suspended.
From discussion here, I conclude that "it could work that way but doesn't."
Userland has to do this (and SUSE's pm-utils actually do. I thought the
Fedora pm-utils also did, but i cannot say for sure). "Just" find out which
entry in menu.lst corresponds to the currently running kernel, and preselect
it for the next boot. It is doable.
So it's a problem of your distro's userland (and if you did not use
pm-hibernate to suspend, it is your very own problem).
You could of course simply go for GRUB's "default saved" and "savedefault"
feature, to always boot the last-booted kernel unless changed in the menu.
I'm being very careful to avoid changing the default boot kernel. If the
system suspends (ie. deliberately) I want to resume in the running
kernel, but if it crashes I want the cold boot to bring up a known
stable kernel, even though that may be lacking in features, have an old
scheduler, etc.
--
bill davidsen <[email protected]>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
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