Date: Sun, 06 Nov 2005 14:44:30 -0800 From: Nate Lawson <nate@root.org> To: Vaibhave Agarwal <vaibhave@cs.utah.edu> Cc: freebsd-net@FreeBSD.org, freebsd-acpi@FreeBSD.org, chris@gnome.co.uk, current@FreeBSD.org, John Baldwin <jhb@FreeBSD.org> Subject: Re: Freebsd 6.0 doesnt detect local APIC on a Pentium 3 machine Message-ID: <436E874E.4010305@root.org> In-Reply-To: <Pine.LNX.4.61.0511061525330.16649@trust.cs.utah.edu> References: <20051027233636.GA39380@dmw.hopto.org> <Pine.LNX.4.61.0510281621120.19263@trust.cs.utah.edu> <Pine.LNX.4.61.0511060450130.4600@trust.cs.utah.edu> <200511061012.57212.jhb@FreeBSD.org> <Pine.LNX.4.61.0511061525330.16649@trust.cs.utah.edu>
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Vaibhave Agarwal wrote:
> On Sun, 6 Nov 2005, John Baldwin wrote:
>
>
>>We don't detect the local APIC via MSR's or the APIC bit in cpu_features, but
>>rely on a working MP Table or MADT table to setup both the local APIC(s) and
>>I/O APIC(s). Does your machine have a valid MP Table or an APIC table in its
>>acpidump? Many UP machine BIOSes don't include those tables.
>>
>
>
> I think you are right.
> There is no valid APIC table in the acpidump.
> The only place where APIC is mentioned in the acpidump(8) is in following:
>
> Scope (\_SB)
> {
> Name (APIC, 0x00)
> Method (_PIC, 1, NotSerialized)
> {
> Store (Arg0, APIC)
> }
> }
>
>
> And I suppose APIC is disabled in the BIOS too.
> Is there a way to enable APIC using software, without changing the BIOS,
> since I dont have access to the BIOS, as it is a remote machine (with
> root access) ?
The above references to APIC just store a value in a convenience
variable. If there's nothing else in the AML that references the
\_SB.APIC variable, then it has no effect on the system. In that case,
the only way to get APIC support on that machine is to implement another
way of enumerating it.
--
Nate
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