Re: Q: swsusp with S5 instead of S4?

From: Ian E. Morgan
Date: Mon May 30 2005 - 14:59:19 EST


On Mon, 2 May 2005, Pavel Machek wrote:

works just fine, in terms of general computing anyways, after resume.

However, some of the ancilary functions, such as LCD brightness, RF kill
switch, and volume mute button do not work after resuming.

Figuring that some hardware parameters were not being restored, I verified
that by forcing a cold boot (boot up to GRUB, issue the 'halt' command to
power off, then power on again and let the kernel resume from swsusp),
everything works perfectly again just as it should because the BIOS takes
care of the initialisation then, which it normally skips after a
soft-off/S4.

Asside from trying to figure out exactly what hardware parameteres are not
being saved/restored, I'm happy to let the BIOS initialise those things.
But, I need a way to perform a normal power-off/S5 after swsusp instead of a
soft-off/S4 so that I don't have to go though the double-grub-boot process
every time. Can this be done?

echo shutdown > /sys/power/disk should do that. If it does
not... well, see what is different in those two codepaths...

I found out that 'shutdown' is the default and that I was already using
that. Strange.

I did finally now get around to doing a more through battery of tests with
many combinations of hibernating with 'platform' and 'shutdown' modes, and
various GRUB 'halt' and 'reboot' commands. What I came up with is that
basically nothing works.

In essentially all cases (except for rare inexplicable instances when it
_does_ work, though I cannot replicate it with any consistency) the special
keys _are_ functional immediately after power-on, through GRUB, through
kernel initialization, through reading the suspended image. But then
immediately after control is passed to the resumed system, the keys stop
working.

Does this give you any other clues as to what might be going on?

Regards,
Ian Morgan

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