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Bug#644550: [egon.eckert@heaven-industries.com: Re: indefinite soft lockup on rm]

Forwarding to the bug log.
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> Version: 3.2~rc4-1~experimental.1
> 
> Egon Eckert wrote:
> 
> > Actually, 3.2.0rc4 seems to run well!  The big (and relevant) change since
> > the squeeze kernel is that the new has the intel_idle driver (which kicks in
> > instead of the acpi_idle):
> 
> Thanks for checking.  Marking accordingly.
> 
> The intel_idle driver was introduced upstream in the 2.6.36 merge
> window and enabled in Debian kernels in 3.1.0-1~experimental.1.
> It would be interesting to hear how a recent kernel built with
> CONFIG_INTEL_IDLE=n behaves, to confirm that that is actually what
> fixed it.

After disabling the intel_idle driver (booting with intel_idle.max_cstate=0,
which effectively disables it) the 3.2.0rc4 kernel installs acpi_idle driver
and crashes again.  The crash, however, doesn't look like the squeeze kernel
crash, so it's not certain they both relate to these C-states.  It's very
similar to the 3.0.0 crash I reported on Oct 25 (in the same bug report
thread).

I also confirmed the squeeze kernel crashes with (C-states enabled in setup)

processor.max_cstate=2

but runs fine with

processor.max_cstate=1

which, interestingly, seems to avoid C-states completely--the
/sys/devices/system/cpu/cpu*/cpuidle directories vanish and idle power
consumption increases to that with C-states disabled in BIOS (the difference
is 20W with/without them, by the way).

Thanks,

-- 
Egon

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