Bug#566208: linux-image-2.6.26-2-486: e_powersaver causes constant lockups

[Moritz Muehlenhoff <jmm@inutil.org>]

On Fri, Jan 22, 2010 at 02:33:27AM +0000, Ben Hutchings wrote:
> On Thu, 2010-01-21 at 19:24 -0500, Ross Vandegrift wrote:
> > Package: linux-image-2.6.26-2-486
> > Version: 2.6.26-19lenny2
> > Severity: critical
> > Justification: breaks the whole system
> > 
> > After upgrading linux-image-2.6.26-2-486 from 17lenny1 to 19lenny2, I
> > started experiencing 100% reproducable system lockups on a VIA C7
> > system.  No errors in the logs, no oops, no BUG, nothing - just a hard
> > lock.  No keyboard LED response and no sysrq functionality worked.
> > 
> > Sometimes the system wouldn't complete the boot process without
> > freezing.  Sometimes it would last three minutes or so before
> > freezing.  I could reproduce the lockup with "cat /dev/zero > file".
> > Every time, within 10 seconds, the system would freeze.
> > 
> > After a lot of trial, error, and searching, I discovered that the
> > e_powersaver module was being loaded and the lockups went away if I
> > unloaded it.
> 
> It is cpufrequtils, not the kernel, that selects which cpufreq driver to
> load, so I will assign this bug to cpufrequtils.
> 
> However, we will reconsider whether this module should be built at all.

X86_E_POWERSAVER is still built as a module in sid. Although the cpufrequtils
blacklist is present in Squeeze, we should probably drop it? After all it's
explicitly marked as dangerous in KConfig.

Cheers,
        Moritz