can't get linux to perform a bios suspend (was: Re: [FIX, please test] Re: 2.5.70-bk16 - nfs interferes with s4bios suspend)

[CaT]

On Wed, Jun 18, 2003 at 12:35:28PM +0200, Pavel Machek wrote:
> > Ponderance: Why did it do a full s/w suspend when I asked for the bios
> > to handle it? I have s4bios showing up in /proc/acpi/sleep and the bios
> > is set to suspend to disk. I've even got an a0 partition fully formatted
> > and it still ignored it all.
> 
> I don't know, try looking at drivers/acpi/sleep/main.c, and if
> neccessary insert some printk()s to see what's going on.

I've had a wee look into it and if I remove software suspend from the
compile, I get no sleep states at all. period. /proc/acpi/sleep does
not exist and nothing is reported in dmesg.

Now I had a look in drivers/acpi/sleep and in the proc.c file I found
this bit of code:

...
        state = simple_strtoul(state_string, NULL, 0);

        if (state < 1 || state > 4)
                goto Done;

        if (!sleep_states[state])
                goto Done;

#ifdef CONFIG_SOFTWARE_SUSPEND
        if (state == 4) {
                software_suspend();
                goto Done;
        }
#endif  
        status = acpi_suspend(state);
...

To me this appears to indicate that it's treating a request for a
sleep state of 4 (s/w suspend) and 4b (bios suspend) as the same thing
as simple_strtoul will stop at the b and return 4 and there are no
further checks being done. In a small experiment I added a test of
state_string[1] == 'b', recompiled and tried it again. It did not go
into s/w suspend as expected but it failed to do a suspend alltogether.

At this point I'm slightly lost. To me it's obvious that there's
something whacky with acpi_suspend() or something it calls but I'm
not sure what. :/

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