Re: [patch 0/4] i386, x86_64: fix the irqbalance quirk forE7520/E7320/E7525

[Andrew Morton]

On Tue, 7 Nov 2006 17:33:06 -0800
"Siddha, Suresh B" <suresh.b.siddha@xxxxxxxxx> wrote:

> Mechanism of selecting physical mode in genapic when cpu hotplug is enabled
> on x86_64, broke the quirk(quirk_intel_irqbalance()) introduced for working
> around the transposing interrupt message errata in E7520/E7320/E7525
> (revision ID 0x9 and below. errata #23 in 
> http://download.intel.com/design/chipsets/specupdt/30304203.pdf).
> 
> This errata requires the mode to be in logical flat, so that interrupts
> can be directed to more than one cpu(and thus use hardware IRQ balancing
> enabled by BIOS on these platforms).
> 
> Following four patches fixes this by moving the quirk to early quirk
> and forcing the x86_64 genapic selection to logical flat on these platforms.
> 
> Thanks to Shaohua for pointing out the breakage.

It blew up with the first config I tried
(http://userweb.kernel.org/~akpm/config-vmm.txt):

arch/i386/kernel/built-in.o: In function `verify_quirk_intel_irqbalance':
arch/i386/kernel/quirks.c:19: undefined reference to `genapic'
arch/i386/kernel/quirks.c:19: undefined reference to `apic_default'
arch/i386/kernel/built-in.o: In function `__cpu_up':
arch/i386/kernel/smpboot.c:1487: undefined reference to `genapic'
arch/i386/kernel/smpboot.c:1487: undefined reference to `apic_default'

The dependencies in the code which you're touching here are really really
complex and fragile.  One needs to review the change very carefully and
test it exhaustively.

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