Re: ACPI and broken PCI IRQ sharing on Asus M5N laptop

From: Len Brown
Date: Sun May 09 2004 - 21:48:47 EST

On Sun, 2004-05-09 at 20:44, Patrick Reynolds wrote:
> I posted yesterday about how the built-in psmouse in my Asus M5N
> (M5200N)
> laptop is broken under recent 2.6 kernels. I believe I have tracked
> the
> problem down to broken IRQ sharing. It's broken under 2.6.2 through
> 2.6.6-rc3-bk11, but it works fine under 2.6.1.
> Booting with default parameters puts the i8042 psmouse channel, the
> Intel
> 8x0 sound card, and the Cardbus controller all on IRQ 12. The mouse
> is
> almost unusable, sampling 3-4 times per second. The sound works
> fine. In
> /proc/interrupts I get
> 12: 310 XT-PIC i8042, Intel 82801DB-ICH4, yenta
> The interrupt count goes up when I play MP3s, but not when I move the
> mouse.

try booting with "acpi_irq_isa=12"

ACPI: PCI Interrupt Link [LNKB] (IRQs 3 4 5 6 7 12) *0, disabled.

ACPI: PCI Interrupt Link [LNKB] enabled at IRQ 12

There are 3 BIOS bugs here:
1. LNKB is marked disabled, yet referenced
Linux handes this

2. Current Setting for LNKB is not in possible setting list
Linux handles -- though apparently this fixes some systems
and breaks others.

3. IRQ12 marked as a viable IRQ for sharing sound and mouse
Linux falls for this hook, line, and sinker.

I'd be interested to see your dmesg and /proc/interrupts from 2.6.1


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