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Message-ID: <3C54A091.DBC545EF@didntduck.org>
Date: Sun, 27 Jan 2002 19:51:29 -0500
From: Brian Gerst <bgerst@didntduck.org>
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To: Jeff Garzik <jgarzik@mandrakesoft.com>
CC: Linus Torvalds <torvalds@transmeta.com>,
        Linux kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Fix NR_IRQS when no IO apic
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Jeff Garzik wrote:
> 
> Brian Gerst wrote:
> >
> > NR_IRQS should be 16 when the IO apic is not configured, as the 8259 PIC
> > cannot generate any more interrupts.  It also fixes a bug where the IDT
> > gets populated with random addresses, since only 16 entry stubs are
> > created.
> 
> > +#ifdef CONFIG_X86_IO_APIC
> >  #define NR_IRQS 224
> > +#else
> > +#define NR_IRQS 16
> > +#endif
> 
> What about when ioapic is configured but not present?

No problem, just wasted memory.  With CONFIG_X86_IO_APIC, all 224 entry
stubs are created.  See arch/i386/kernel/i8259.c

-- 

						Brian Gerst
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