Re: 2.6.27-rc5 doesn't boot on a Pavilion laptop

[Thomas Gleixner]

Luiz,

On Tue, 2 Sep 2008, Luiz Fernando N. Capitulino wrote:
> 
>  I have a HP Pavilion dv6000 laptop here which doesn't boot with
> latest Linus tree (2.6.27-rc5).
> 
>  The last lines I see on the screen are:
> 
> """
> hpet0: at MMIO 0xfed00000, IRQs 2, 8, 31
> hpet0: 3 32-bit timers, 25 000000 Hz
> """

Sigh. I'm getting sick of that :)
 

>  Then I bisected and git says that the culprit is:
> 
> """
> commit aa276e1cafb3ce9d01d1e837bcd67e92616013ac
> Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Date:   Mon Jun 9 19:15:00 2008 +0200
> 
>     x86, clockevents: add C1E aware idle function

Not surprising :)

>  Now, what puzzles me though is that if you do:
> 
> $ git checkout -b bla aa276e1cafb3ce9d01d1e837bcd67e92616013ac
> 
>  and edit the Makefile you will see that it is a 2.6.26-rc4
> kernel! When I saw this I thought 'wth? git bisect went backwards?'
> (I specified 2.6.26 as good and 2.6.27-rc1 as bad).

That's because the commit happened in the x86 git tree after
2.6.26-rc4. In fact you checked out the branch of the x86 git tree
where the commit happened.

>  I don't know if this is known (it should be) but it seems that you
> have changed the Makefile during the merge of that commit... But
> I'm quite sure that this commit has been introduced in 2.6.27-rc1.

Yes, it was merged into Linus tree after 2.6.26 and before
2.6.27-rc1. That's how git works. It keeps track from which point a
particular commit descended. If you look at the git tree with gitk,
then you will see the various points where a particular branch was
split off from Linus tree and when it was merged back.

Nothing to worry about.
 
>  I would try to revert it from current Linus' tree to see if it
> really fix the problem but turns out that it will take some time
> to work on the conflicts.

Don't do that. We really need to find out what the root cause of this
HPET wreckage on those AMD machine is. The commit in question _IS_ the
alleged culprit, but the root cause is something different.

>  I'm attaching the 2.6.26.3 (Mandriva kernel) and 2.6.27-rc5 (with
> hpet=disable) dmesg files.
> 
>  Also, this _seems_ to be the same as reported in:
> 
> http://bugzilla.kernel.org/show_bug.cgi?id=11191

Yup.
 
>  But I'm still compiling the kernel with the appropriate config
> options to confirm this.
> 
>  Please, let me know if there's anything else I can do to
> help you debug this.

Can you please disable CONFIG_HPET ?

Thanks,

	tglx
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