[PATCH -tip] x86,apic -- don't forget to disconnect BSP discrete apic

[PATCH -tip] x86,apic -- don't forget to disconnect BSP discrete apic

[Cyrill Gorcunov]

In case of discrete APIC cpu_has_apic could be not set.
This leads to disconnect_bsp_APIC is not called where
it should.

Tested-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
---

Please review.

 arch/x86/kernel/apic/io_apic.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.git/arch/x86/kernel/apic/io_apic.c
=====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/apic/io_apic.c
+++ linux-2.6.git/arch/x86/kernel/apic/io_apic.c
@@ -2002,7 +2002,7 @@ void disable_IO_APIC(void)
 	/*
 	 * Use virtual wire A mode when interrupt remapping is enabled.
 	 */
-	if (cpu_has_apic)
+	if (cpu_has_apic || smp_found_config)
 		disconnect_bsp_APIC(!intr_remapping_enabled &&
 				ioapic_i8259.pin != -1);
 }

Re: [PATCH -tip] x86,apic -- don't forget to disconnect BSP discrete apic

[H. Peter Anvin]

Cyrill Gorcunov wrote:
> In case of discrete APIC cpu_has_apic could be not set.
> This leads to disconnect_bsp_APIC is not called where
> it should.

I thought we were going to turn on cpu_has_apic in this case?

	-hpa

Re: [PATCH -tip] x86,apic -- don't forget to disconnect BSP discrete apic

[Cyrill Gorcunov]

On 7/9/09, H. Peter Anvin <hpa@zytor.com> wrote:
> Cyrill Gorcunov wrote:
>> In case of discrete APIC cpu_has_apic could be not set.
>> This leads to disconnect_bsp_APIC is not called where
>> it should.
>
> I thought we were going to turn on cpu_has_apic in this case?
>
> 	-hpa
>
>
Yes, this is just a temporary fix. I'll remove this snippet as only
cpu-has-apic patch will be ready (i need to re-check all ways and and
i need some time for this. Hope will finish it at weekend). Dunno
Peter. If there is no urgency -- lets mark that we have this temporary
workaround in lklm and if we get kind of bugreport we could apply the
patch shortly :)

Re: [PATCH -tip] x86,apic -- don't forget to disconnect BSP discrete apic

[H. Peter Anvin]

Cyrill Gorcunov wrote:
> On 7/9/09, H. Peter Anvin <hpa@zytor.com> wrote:
>> Cyrill Gorcunov wrote:
>>> In case of discrete APIC cpu_has_apic could be not set.
>>> This leads to disconnect_bsp_APIC is not called where
>>> it should.
>> I thought we were going to turn on cpu_has_apic in this case?
>>
>> 	-hpa
>>
>>
> Yes, this is just a temporary fix. I'll remove this snippet as only
> cpu-has-apic patch will be ready (i need to re-check all ways and and
> i need some time for this. Hope will finish it at weekend). Dunno
> Peter. If there is no urgency -- lets mark that we have this temporary
> workaround in lklm and if we get kind of bugreport we could apply the
> patch shortly :)


Since discrete-APIC systems are so old and rare I think it can wait for
the proper fix, however, as you said, if there are unexpected problems
we can reconsider.

	-hpa


-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.