PATCH/RFC: [kdump] fix APIC shutdown sequence
martin.wilck at fujitsu-siemens.com
Wed Aug 8 05:03:17 EDT 2007
> How bad is it if you just run with irqpoll in the kdump kernel?
> If running with irqpoll is usable that is probably preferable
> to putting in a hardware work around we can survive without.
Yes, I tried that. No effect.
> Have you done any looking at moving where the kernel initalizes
> io_apics? One of the todo items on the path is to leave
> io_apic mode enabled and just startup the kernel in io_apic
I have tried to recover from the "IRR set" situation in several ways by
changing setup_IO_APIC_irq(). But I haven't found a way to recover from
this situation once disable_IO_APIC() had been called.
I concluded thatthe sequence of events
"send INT message - never receive EOI - disable IO-APIC pin"
messes up the IO-APIC (at least this specific one in the
PCIEx-PCI bridge of the ICH7).
The current state of affairs is that the only thing that "worked" was to
> When doing that a version of your work around (if needed)
> would certainly be reasonable.
> My general concern is that the trickier we get in the code
> running in the crashed kernel the less reliable the entire
> process will be.
That's certainly correct. I am grateful for all hints that simplify my patch.
PRIMERGY System Software Engineer
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Fujitsu Siemens Computers GmbH
Tel: ++49 5251 8 15113
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Email: mailto:martin.wilck at fujitsu-siemens.com
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