Re: [linux-pm] [RFC] ACPI vs device ordering on resume

[Pavel Machek <pavel@ucw.cz>]

Hi!

> > So it looks like we need this sequence:
> > 
> > enable_nonboot_cpus() /* INIT */
> > finish()	/* _WAK */
> > device_resume()
> 
> Can somebody remind me about this immediately after 2.6.19?

Remind. But note that freezer is not yet SMP safe... Rafael is working
on that.
								Pavel

> No way am I going to make that kind of a major ordering change right now, 
> especially as the thing isn't apparently even a real regression (just more 
> fallout from enabling MSI).
> 
> It would be good if people who are affected (and people in general that 
> are interested in power management) would test out the patch.
> 
> In particular, this is an even bigger change than the one suggested by 
> Stephen. It means, for example, that we will have device resume (and 
> process thawing) being called when we're in SMP mode - and that may or may 
> not have issues. So this is a really scary patch to me, no way in hell 
> will I apply it right now.
> 
> But if people try it out, it would be good..
> 
> Btw, this is a clear example of where it might be good to start actively 
> using the "early_resume" thing, and do PCI bus resume there. We might want 
> to do early_resume _before_ calling the bios (I'm not at all convinced 
> that the firmware will do the right thing without the PCI buses set up, 
> for example), and _before_ thawing processes. Then, we might let 
> individual devices do their "device resume" in the normal late resume 
> phase.
> 
> Greg already carries the patch around for that PCI bus early resume thing, 
> I think. 
> 
> We need to test these things.
> 
> 		Linus
> 
> ----
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index 873228c..2989609 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -132,12 +132,12 @@ int suspend_enter(suspend_state_t state)
>  
>  static void suspend_finish(suspend_state_t state)
>  {
> -	device_resume();
> -	resume_console();
> -	thaw_processes();
>  	enable_nonboot_cpus();
>  	if (pm_ops && pm_ops->finish)
>  		pm_ops->finish(state);
> +	device_resume();
> +	resume_console();
> +	thaw_processes();
>  	pm_restore_console();
>  }
>  

-- 
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