Re: 2.6.19-rc4: known unfixed regressions (v3)

[Len Brown <len.brown@intel.com>]

On Monday 06 November 2006 21:17, Ernst Herzberg wrote:
> On Sunday 05 November 2006 07:48, Adrian Bunk wrote:
> > ...
> > Subject    : ThinkPad R50p: boot fail with (lapic && on_battery)
> > References : http://lkml.org/lkml/2006/10/31/333
> > Submitter  : Ernst Herzberg <earny@net4u.de>
> > Status     : problem is being debugged
> =

> Update:
> =

> 2.6.19-rc4-git11 does _not_ fix the problem.
> =

> But now it doesn't matter if Cardbus/PCMCIA is compiled in or not.
> =

> What also matters is a setting in the BIOS:
> =

> If i set instead of
> =

> Power -> =

>    SpeedStep ->
>       Mode for AC -    "Max Performance"
>       Mode for Battery "Max Battery"
> =

> to
> =

> Power -> =

>    SpeedStep ->
>       Mode for AC -    "Max Battery"
>       Mode for Battery "Max Performance" =

> =

> he _does_ boot from battery but also on AC...

so with the new settings it boots properly in either AC or battery mode wit=
h forced "lapic"?
Strange, one would expect this to refer to APM settings, but who knows...

Please test if booting with "processor.max_cstate=3D1" makes any difference

Please test if building with CONFIG_CPU_FREQ=3Dn makes any difference.

Also, please make sure that booting with "apm=3Doff" makes no difference --
there is a bug where the APM code is not currently disabled in ACPI mode,
and who knows what effect that may have...

> Also the problem is now(?) not very reliable. Sometimes the boot is succe=
ssful =

> even on battery and then the laptop works without a glitch.
> This makes it not easier to isolate the problem.
> =


> Is somewhere a howto-revert-patches-in-kernel-git-for-raw-beginners?

Documentation/git-bisect.txt is what you want -- though if you can't
reliably reproduce the failure it may not easily lead you to the failure.

Also, it may be a good use of time to make darn sure that booting 2.6.18
with forced "lapic" when on battery does not fail.  ie. is this really
a regression -- of did forcing the lapic on this box never work reliably?

-Len