* [PATCH][2.5.73] enable local APIC on P4
@ 2003-06-23 22:29 Mikael Pettersson
2003-06-23 22:45 ` Davide Libenzi
0 siblings, 1 reply; 2+ messages in thread
From: Mikael Pettersson @ 2003-06-23 22:29 UTC (permalink / raw)
To: torvalds; +Cc: kaos, linux-kernel
The current local APIC code refuses to enable the local APIC
on a P4 if the BIOS booted us with the local APIC disabled.
This patch removes this unnecessary restriction. Please apply.
Most P4 machines do boot with the local APIC enabled, but
Keith Owens reported that the P4 based Compaq Evo N800v
disables the local APIC, even though the machine actually
works if Linux enables it.
It is possible that some P4 machines with broken BIOSen
were saved by our refusal to enable the local APIC. We
can handle them via the DMI blacklist rules instead.
/Mikael
--- linux-2.5.73/arch/i386/kernel/apic.c.~1~ 2003-06-17 12:51:19.000000000 +0200
+++ linux-2.5.73/arch/i386/kernel/apic.c 2003-06-23 23:00:20.000000000 +0200
@@ -616,7 +616,7 @@
goto no_apic;
case X86_VENDOR_INTEL:
if (boot_cpu_data.x86 == 6 ||
- (boot_cpu_data.x86 == 15 && cpu_has_apic) ||
+ boot_cpu_data.x86 == 15 ||
(boot_cpu_data.x86 == 5 && cpu_has_apic))
break;
goto no_apic;
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH][2.5.73] enable local APIC on P4
2003-06-23 22:29 [PATCH][2.5.73] enable local APIC on P4 Mikael Pettersson
@ 2003-06-23 22:45 ` Davide Libenzi
0 siblings, 0 replies; 2+ messages in thread
From: Davide Libenzi @ 2003-06-23 22:45 UTC (permalink / raw)
To: Mikael Pettersson; +Cc: Linus Torvalds, kaos, Linux Kernel Mailing List
On Tue, 24 Jun 2003, Mikael Pettersson wrote:
> The current local APIC code refuses to enable the local APIC
> on a P4 if the BIOS booted us with the local APIC disabled.
> This patch removes this unnecessary restriction. Please apply.
>
> Most P4 machines do boot with the local APIC enabled, but
> Keith Owens reported that the P4 based Compaq Evo N800v
> disables the local APIC, even though the machine actually
> works if Linux enables it.
>
> It is possible that some P4 machines with broken BIOSen
> were saved by our refusal to enable the local APIC. We
> can handle them via the DMI blacklist rules instead.
I did the same thing on my Presario. BIOS disable it by default.
- Davide
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2003-06-23 22:33 UTC | newest]
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2003-06-23 22:29 [PATCH][2.5.73] enable local APIC on P4 Mikael Pettersson
2003-06-23 22:45 ` Davide Libenzi
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