Linus Torvalds <[email protected]> writes:
> Of course, for edge-triggered APIC interrupts, we _have_ to replay the irq
> (since we don't have any way of even *knowing* whether we might get it
> again), but for level-triggered and for the old legacy i8259 controller
> that gets it right for edges anwyay, we should _not_ send the spurious
> interrupt that is no longer active.
>
> And a lot of code has been tested with either just the i8259 (old machines
> without any APIC) or with PCI-only devices (which are always level-
> triggered), so the fact that edge-triggered things have always seen the
> potential for spurious interrupts is not a reasong to say "well, they have
> to handle it anyway". True PCI drivers generally do _not_ have to handle
> the crazy case, and generally have never seen it.
>
> In other words, I think we should just make APIC-edge have the "please
> delay masking and replay" bit, and nobody else.
>
> Can you send that patch (for both x86 and x86-64), and we can ask Komuro
> to test it. That would be the "same behaviour as we've always had" thing,
> which I think is also the _right_ behaviour.
Hopefully this is the trivial patch that solves the problem.
Signed-off-by: Eric W. Biederman <[email protected]>
diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index ad84bc2..3b7a63e 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -1287,9 +1287,11 @@ static void ioapic_register_intr(int irq
trigger == IOAPIC_LEVEL)
set_irq_chip_and_handler_name(irq, &ioapic_chip,
handle_fasteoi_irq, "fasteoi");
- else
+ else {
+ irq_desc[irq].status |= IRQ_DELAYED_DISABLE;
set_irq_chip_and_handler_name(irq, &ioapic_chip,
handle_edge_irq, "edge");
+ }
set_intr_gate(vector, interrupt[irq]);
}
diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index 41bfc49..14654e6 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -790,9 +790,11 @@ static void ioapic_register_intr(int irq
trigger == IOAPIC_LEVEL)
set_irq_chip_and_handler_name(irq, &ioapic_chip,
handle_fasteoi_irq, "fasteoi");
- else
+ else {
+ irq_desc[irq].status |= IRQ_DELAYED_DISABLE;
set_irq_chip_and_handler_name(irq, &ioapic_chip,
handle_edge_irq, "edge");
+ }
}
static void __init setup_IO_APIC_irqs(void)
-
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