* [PATCH] Fix NR_IRQS when no IO apic
@ 2002-01-28 0:27 Brian Gerst
2002-01-28 0:42 ` Jeff Garzik
0 siblings, 1 reply; 4+ messages in thread
From: Brian Gerst @ 2002-01-28 0:27 UTC (permalink / raw)
To: Linus Torvalds; +Cc: Linux kernel mailing list
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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.
--
Brian Gerst
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diff -urN linux-2.5.3-pre5/include/asm-i386/irq.h linux/include/asm-i386/irq.h
--- linux-2.5.3-pre5/include/asm-i386/irq.h Fri Jan 25 02:25:47 2002
+++ linux/include/asm-i386/irq.h Fri Jan 25 11:30:44 2002
@@ -23,7 +23,11 @@
* Since vectors 0x00-0x1f are used/reserved for the CPU,
* the usable vector space is 0x20-0xff (224 vectors)
*/
+#ifdef CONFIG_X86_IO_APIC
#define NR_IRQS 224
+#else
+#define NR_IRQS 16
+#endif
static __inline__ int irq_cannonicalize(int irq)
{
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Fix NR_IRQS when no IO apic
2002-01-28 0:27 [PATCH] Fix NR_IRQS when no IO apic Brian Gerst
@ 2002-01-28 0:42 ` Jeff Garzik
2002-01-28 0:51 ` Brian Gerst
2002-01-28 1:07 ` Robert Love
0 siblings, 2 replies; 4+ messages in thread
From: Jeff Garzik @ 2002-01-28 0:42 UTC (permalink / raw)
To: Brian Gerst; +Cc: Linus Torvalds, Linux kernel mailing list
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?
Jeff
--
Jeff Garzik | "I went through my candy like hot oatmeal
Building 1024 | through an internally-buttered weasel."
MandrakeSoft | - goats.com
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Fix NR_IRQS when no IO apic
2002-01-28 0:42 ` Jeff Garzik
@ 2002-01-28 0:51 ` Brian Gerst
2002-01-28 1:07 ` Robert Love
1 sibling, 0 replies; 4+ messages in thread
From: Brian Gerst @ 2002-01-28 0:51 UTC (permalink / raw)
To: Jeff Garzik; +Cc: Linus Torvalds, Linux kernel mailing list
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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Fix NR_IRQS when no IO apic
2002-01-28 0:42 ` Jeff Garzik
2002-01-28 0:51 ` Brian Gerst
@ 2002-01-28 1:07 ` Robert Love
1 sibling, 0 replies; 4+ messages in thread
From: Robert Love @ 2002-01-28 1:07 UTC (permalink / raw)
To: Jeff Garzik; +Cc: Brian Gerst, Linus Torvalds, Linux kernel mailing list
On Sun, 2002-01-27 at 19:42, Jeff Garzik wrote:
> What about when ioapic is configured but not present?
Then we are back where we started? Which, unless I am missing
something, is just a waste of memory?
I see this as a no-change if CONFIG_X86_IO_APIC is set, but a proper
setting of NR_IRQS (which doesn't hurt anything but make our
arrays/loops/etc off if not set) for the case of non-IOAPIC.
Robert Love
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2002-01-28 1:02 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2002-01-28 0:27 [PATCH] Fix NR_IRQS when no IO apic Brian Gerst
2002-01-28 0:42 ` Jeff Garzik
2002-01-28 0:51 ` Brian Gerst
2002-01-28 1:07 ` Robert Love
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