[LinuxBIOS] RE: x86_64: calibrate_delay_direct and apic id lift for BSP

Lu, Yinghai yinghai.lu at amd.com
Fri Oct 28 21:49:06 CEST 2005

I have tried latest code..., except that, it works well.


-----Original Message-----
From: Andi Kleen [mailto:ak at suse.de] 
Sent: Friday, October 28, 2005 11:53 AM
To: Lu, Yinghai
Cc: discuss at x86-64.org; linux-kernel at vger.kernel.org;
linuxbios at openbios.org
Subject: Re: x86_64: calibrate_delay_direct and apic id lift for BSP

On Friday 28 October 2005 20:42, Yinghai Lu wrote:
> andi,
> I tried to lift apic id in LinuxBIOS for all cpus after 0x10.
> When using MB with AMD8111, the jiffies was not moving. So it is
> locked at calibrate_delay_direct...

Have you tried it with 2.6.14? It has some new code to handle
high apic ids better
> but  MB with Nvidia ck804, jiffies is moving.

The timer is wired different on nvidia than on 8111. They can
go either through the 8259 or through the IOAPIC.  There is still
some code that falls back to the 8259 if IOAPIC doesn't work,
which may make it appear working on Nvidia.

As a warning I'm about to remove that code so don't rely on it.

> If I don't change BSP apic id ( keep it to 0), It changes....
> I have no idea how the jiffies changes, there is another thread change

They change when interrupt 0 fires. So it's probably misrouted
or similar.


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