On Tue, Dec 6, 2011 at 11:46, Russell King - ARM Linux
[off-list ref] wrote:

But.. let's make one thing clear: Alan Cox and Linus have been going on
about how IRQ0 should not be used. ?Let's be crystal clear: even x86
uses IRQ0. ?It happens to be the PIC timer, and that gets claimed early
on during the x86 boot. ?So please don't tell me that x86 avoids IRQ0.
It doesn't. ?It just happens that x86 never shows IRQ0 to anything but
the i8253 PIC driver.

It's shown in /proc/interrupts due to a "bug" in show_interrupts().
The (gmail damaged) patch below fixes this bug.

From 46f51a2d42548358868a34df00c2a4e47bbdf691 Mon Sep 17 00:00:00 2001

From: Geert Uytterhoeven <redacted>
Date: Tue, 6 Dec 2011 11:55:05 +0100
Subject: [PATCH] /proc/interrupts: irq zero is invalid

As zero is an invalid irq number, show_interrupts() should not try to
print it. Just return after printing the header for i == 0.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 kernel/irq/proc.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 4bd4faa..5b8bbf0 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c

@@ -439,6 +439,7 @@ int show_interrupts(struct seq_file *p, void *v)
 		for_each_online_cpu(j)
 			seq_printf(p, "CPU%-8d", j);
 		seq_putc(p, '\n');
+		return 0;
 	}

 	desc = irq_to_desc(i);

-- 
1.7.0.4

Gr{oetje,eeting}s,

? ? ? ? ? ? ? ? ? ? ? ? Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
? ? ? ? ? ? ? ? ? ? ? ? ? ?? ?? -- Linus Torvalds