Re: Local APIC bug?

Re: Local APIC bug?

[Michael Schierl]

On Sat, 27 Dec 2003 21:00:06 +0100, in linux.kernel you wrote:

>> However, I'd appreciate if someone had any idea why the kernel crashes
>> when trying to resume. Deadlocks...?
>
>most bioses on laptops that I have seen don't actually restore the apic
>state on resume (since they don't expect the apic to be used at all)
>which results in entirely horked irq's on resume -> kernel crashes.

Thanks. However, my laptop crashes on *suspend* when APIC is on and on
*resume* when APIC is off...

And on -test3 it did not crash. 

jftr: on 2.4.x it crashed on resume as well. Someone trying to prevent
me to use stable kernels on my laptop? ;-(

Michael
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Re: Local APIC bug?

[Mikael Pettersson]

On Sun, 28 Dec 2003 21:07:28 +0100, Michael Schierl wrote:
>>> However, I'd appreciate if someone had any idea why the kernel crashes
>>> when trying to resume. Deadlocks...?
>>
>>most bioses on laptops that I have seen don't actually restore the apic
>>state on resume (since they don't expect the apic to be used at all)
>>which results in entirely horked irq's on resume -> kernel crashes.

Our local APIC PM code saves the local APIC state and disables it
before suspend, and restores it and reenables the local APIC after
resume.

>Thanks. However, my laptop crashes on *suspend* when APIC is on and on
>*resume* when APIC is off...
>
>And on -test3 it did not crash. 
>
>jftr: on 2.4.x it crashed on resume as well. Someone trying to prevent
>me to use stable kernels on my laptop? ;-(

Do you use APM? How do you suspend? With "apm --suspend" or by e.g.
closing the lid? In the latter case, does your APM BIOS post the
suspend event to us before actually suspending?

An APM BIOS that crashes in SMM code before posting the suspend event,
or that skips posting the event altogether, probably won't work with
an enabled local APIC. Not much we can do about that.

/Mikael

Re: Local APIC bug?

[Michael Schierl]

Mikael Pettersson schrieb:
> 
> On Sun, 28 Dec 2003 21:07:28 +0100, Michael Schierl wrote:
> >>> However, I'd appreciate if someone had any idea why the kernel crashes
> >>> when trying to resume. Deadlocks...?
> >>
> >>most bioses on laptops that I have seen don't actually restore the apic
> >>state on resume (since they don't expect the apic to be used at all)
> >>which results in entirely horked irq's on resume -> kernel crashes.
> 
> Our local APIC PM code saves the local APIC state and disables it
> before suspend, and restores it and reenables the local APIC after
> resume.
> 
> >Thanks. However, my laptop crashes on *suspend* when APIC is on and on
> >*resume* when APIC is off...
> >
> >And on -test3 it did not crash.
> >
> >jftr: on 2.4.x it crashed on resume as well. Someone trying to prevent
> >me to use stable kernels on my laptop? ;-(
> 
> Do you use APM? How do you suspend? With "apm --suspend" or by e.g.
> closing the lid? In the latter case, does your APM BIOS post the
> suspend event to us before actually suspending?

I suspend by "apm -s". I disabled Suspending by closing the lid or by
Fn+F4 because it happens when I don't like it then, which can be fatal
when resume does not work.

My "test scenario" is doing an "apm -s" when booted with
"init=/bin/bash", having done nothing else than mounted /proc.

tried that with -test4 to -test11, final, and -mm1. All without success.
I can move the point where it crashes around (when I have yenta support
in, it crashes before displaying the prompt again, without it crashes
after displaying it (however, further commands i append by ";" to the
apm command are not executed or only print their first line of output;
so it is most likely not the keyboard driver which is broken). With
local apic it crashes before it suspends. I hoped this would help you to
track down the bug, but it seems that all this behaviour is normal (with
apic), except that without apic it should work...

> An APM BIOS that crashes in SMM code before posting the suspend event,
> or that skips posting the event altogether, probably won't work with
> an enabled local APIC. Not much we can do about that.

I'd like it if you could make my laptop suspend again *without* local
apic. (or better, resume). It works on 2.6.0-test3, whatever i do, but i
don't manage to get it working on later kernels.

And I do *not* like to run beta kernels on production machines, you
mightt understand that...

Till 2.4.x, i believed that the apm of my notebook cannot be made
working with linux - but -test1 to -test3 (I did not try any 2.5
kernels) showed me that it is possible to resume it. Just that it seems
to be impossible with a "stable" kernel. (is that Murphy?)

Michael