Re: 2.6.23-rc6-mm1: failure to boot on HP nx6325, no sound when booted, USB-related WARNING

[Len Brown <lenb@kernel.org>]

On Thursday 20 September 2007 17:55, Linus Torvalds wrote:
> 
> On Thu, 20 Sep 2007, Linus Torvalds wrote:
> > 
> > (Btw, the above commit message points to just my response with a testing 
> > patch to the real email: the actual explanation of the INSANE ordering is 
> > from Len Brown in
> > 
> > 	https://lists.linux-foundation.org/pipermail/linux-pm/2006-November/004161.html
> > 
> > and there Len claims that we *must* wake up CPU's early).
> 
> ..and points to commit 1a38416cea8ac801ae8f261074721f35317613dc which in 
> turn talks about http://bugzilla.kernel.org/show_bug.cgi?id=5651 
> 
> Howerver, it seems that bugzilla entry may just be bogus. It talks about 
> "it appears that some firmware in the future may depend on that sequence 
> for correction operation"
> 
> Len, Shaohua, what are the real issues here? 

Intel's reference BIOS for Core Duo performs some re-initialization
in _WAK that will get blow away if INIT follows _WAK.
IIR, it is related to re-initializing the thermal sensors.
I opened bug 5651 when the BIOS team informed me of this issue.

Yes, bringing a processor offline and then online again w/o
an intervening suspend or reset would not evaluate _WAK,
and thus may still run into the issue.

I don't know if this is a widespread issue and a commonly
used BIOS hook, or if it is specific to certain processors.

-Len

> It would indeed be nice if we could just take CPU's down early (while 
> everything is working), and run the whole suspend code with just one CPU, 
> rather than having to worry about the ordering between CPU and device 
> takedown.
> 
> That said, at least with STR, the situation is:
> 
>  1) suspend_console
>  2)   device_suspend(PMSG_SUSPEND)	  (==   ->suspend)
>  3)     disable_nonboot_cpus()
>  4)       device_power_down(PMSG_SUSPEND) (==   ->suspend_late)
>  5)         pm_ops->enter()
>  6)       device_power_up()		  (==   ->resume_early)
>  7)     enable_nonboot_cpus()
>  8)     pm_finish()
>  9)   device_resume()		          (==   ->resume
> 10) resume_console
> 
> So if we agree that things like timers etc should *never* be suspended by 
> the early suspend, and *always* use "suspend_late/resume_early", then at 
> least STR should be ok.
> 
> And I think that's a damn reasonable thing to agree on: timers (and 
> anything else that CPU shutdown/bringup could *possibly* care about) 
> should be considered core enough that they had better be on the 
> suspend_late/resume_early list.
> 
> Thomas, Rafael, can you verify that at least STR is ok in this respect?
> 
> 		Linus
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