Re: irq again

Len Brown
2003-12-08T19:42:09Z

If the Dell has an IO-APIC, you want to build support for it into the
kernel -- doing so may free up some additional interrupt lines.

If you can upgrade to the 2.4.23 kernel and run in ACPI mode, then there
are a couple of knobs that might be able to help you.

acpi_irq_balance ACPI will balance active IRQs
acpi_irq_nobalance ACPI will not move active IRQs
acpi_irq_pci= If irq_balance, Clear listed IRQs for use by PCI
acpi_irq_isa= If irq_balance, Mark listed IRQs used by ISA

acpi_irq_balance is default in IOAPIC mode
acpi_irq_nobalance is default in PIC mode
the acpi_irq_[pci, isa] are to list specify IRQs that should, and should
not be used for PCI interrupts, respectively.

cheers,
-Len

ps. Might also try to disable USB in the BIOS and use a PS/2 keyboard to
free up the IRQs?

On Mon, 2003-12-08 at 13:58, Jing Xu wrote:
> Hi, guys,
>
> I have been stuct on this problem for a long time. Any
> suggestion on this will be highly appreciated.
>
> I'm running linux 2.4.20 and rtai 24.1.11. My linux
> kernel module needs to use IRQ 9 10 11 for AGP graphic
> card, sound card and PCI-Dio24 IO card. These irqs are
> also shared by USB controllers. My module hangs when
> it tries to request one of the above irqs that is used
> by USB keyboard.
>
> I am using DELL machine, and its bios cannot reserve
> irq's.
>
> I also tried to set boot paramter "pci=irqmask=0xf1ef"
> to reserve irqs 9 10 11 4 for my driver, and it hasn't
> had any effect - those irqs are still used by usb
> controllers on initialization.
>
> How to solve this irq confliction problem?
>
> Thanks in advance,
>
> jing
>
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