[PATCH 1/3] x86: L-APIC: Set IRQ0 as edge-triggered

From: Maciej W. Rozycki
Date: Fri Jul 11 2008 - 14:37:53 EST


IRQ0 is edge-triggered, but the "8259A Virtual Wire" through the local
APIC configuration in the 32-bit version uses the "fasteoi" handler
suitable for level-triggered APIC interrupt. Rewrite code so that the
"edge" handler is used. The 64-bit version uses different code and is
unaffected.

Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
Cc: Andreas Herrmann <andreas.herrmann3@xxxxxxx>
---

Note this is against linux-next.

patch-next-2.6.26-rc9-20080711-timer-lapic-edge-7
diff -up --recursive --new-file linux-next-2.6.26-rc9-20080711.macro/arch/x86/kernel/io_apic_32.c linux-next-2.6.26-rc9-20080711/arch/x86/kernel/io_apic_32.c
--- linux-next-2.6.26-rc9-20080711.macro/arch/x86/kernel/io_apic_32.c 2008-07-11 17:10:33.000000000 +0000
+++ linux-next-2.6.26-rc9-20080711/arch/x86/kernel/io_apic_32.c 2008-07-11 17:51:05.000000000 +0000
@@ -2052,7 +2052,7 @@ static struct irq_chip lapic_chip __read
.name = "local-APIC",
.mask = mask_lapic_irq,
.unmask = unmask_lapic_irq,
- .eoi = ack_apic,
+ .ack = ack_apic,
};

static void __init setup_nmi(void)
@@ -2257,8 +2257,8 @@ static inline void __init check_timer(vo

printk(KERN_INFO "...trying to set up timer as Virtual Wire IRQ...");

- set_irq_chip_and_handler_name(0, &lapic_chip, handle_fasteoi_irq,
- "fasteoi");
+ set_irq_chip_and_handler_name(0, &lapic_chip, handle_edge_irq,
+ "edge");
apic_write_around(APIC_LVT0, APIC_DM_FIXED | vector); /* Fixed mode */
enable_8259A_irq(0);

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