* x86: meaning of nolapic command line option
@ 2009-01-09 17:00 Jan Beulich
2009-01-11 2:46 ` Ingo Molnar
0 siblings, 1 reply; 3+ messages in thread
From: Jan Beulich @ 2009-01-09 17:00 UTC (permalink / raw)
To: mingo, tglx, hpa; +Cc: linux-kernel
Shouldn't that option imply that all APIC related activity, including that relating to IO-APICs or PCI MSI, should be circumvented? I'm finding that MSI must be disabled separately, and while most of the IO-APIC stuff is indeed not happening, acpi_get_override_irq() only checks skip_ioapic_setup, but that doesn't normally set without the noapic command line option.
Is there any reason pci_no_msi() and disable_ioapic_setup() shouldn't be called when !cpu_has_apic at the end of identify_cpu()?
Thanks, Jan
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: x86: meaning of nolapic command line option
2009-01-09 17:00 x86: meaning of nolapic command line option Jan Beulich
@ 2009-01-11 2:46 ` Ingo Molnar
2009-01-13 8:19 ` Jan Beulich
0 siblings, 1 reply; 3+ messages in thread
From: Ingo Molnar @ 2009-01-11 2:46 UTC (permalink / raw)
To: Jan Beulich; +Cc: tglx, hpa, linux-kernel
* Jan Beulich <jbeulich@novell.com> wrote:
> Shouldn't that option imply that all APIC related activity, including
> that relating to IO-APICs or PCI MSI, should be circumvented? I'm
> finding that MSI must be disabled separately, and while most of the
> IO-APIC stuff is indeed not happening, acpi_get_override_irq() only
> checks skip_ioapic_setup, but that doesn't normally set without the
> noapic command line option.
>
> Is there any reason pci_no_msi() and disable_ioapic_setup() shouldn't be
> called when !cpu_has_apic at the end of identify_cpu()?
Yes, both depend on a lapic and they might limp on with whatever the BIOS
gave us, you are right that it should be disabled explicitly. Mind sending
a patch?
Ingo
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: x86: meaning of nolapic command line option
2009-01-11 2:46 ` Ingo Molnar
@ 2009-01-13 8:19 ` Jan Beulich
0 siblings, 0 replies; 3+ messages in thread
From: Jan Beulich @ 2009-01-13 8:19 UTC (permalink / raw)
To: Ingo Molnar; +Cc: tglx, linux-kernel, hpa
>>> Ingo Molnar <mingo@elte.hu> 11.01.09 03:46 >>>
>
>* Jan Beulich <jbeulich@novell.com> wrote:
>
>> Shouldn't that option imply that all APIC related activity, including
>> that relating to IO-APICs or PCI MSI, should be circumvented? I'm
>> finding that MSI must be disabled separately, and while most of the
>> IO-APIC stuff is indeed not happening, acpi_get_override_irq() only
>> checks skip_ioapic_setup, but that doesn't normally set without the
>> noapic command line option.
>>
>> Is there any reason pci_no_msi() and disable_ioapic_setup() shouldn't be
>> called when !cpu_has_apic at the end of identify_cpu()?
>
>Yes, both depend on a lapic and they might limp on with whatever the BIOS
>gave us, you are right that it should be disabled explicitly. Mind sending
>a patch?
I will - just wanted to see whether there's some hidden reason behind the
current way this is coded. Actually, I meanwhile realized that doing this
somply based on !cpu_has_apic wouldn't be right, it should (at least for
32-bits) also depend on APIC_INTEGRATED() - just like e.g. done in
APIC_init_uniprocessor().
Jan
^ permalink raw reply [flat|nested] 3+ messages in thread
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2009-01-09 17:00 x86: meaning of nolapic command line option Jan Beulich
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