[linux-audio-user] IRQ conflicts, acpi, and linux audio

Mark Knecht markknecht at gmail.com
Sat Nov 26 20:40:24 EST 2005

On 11/19/05, thewade <pdman at aproximation.org> wrote:
> Hello pd and lau lists,


> I am having trouble figuring out how to actually change the irq's of specific devices.

I am not sure of the motherboard in this laptop

Changing interrupt priorities of internal devices on a laptop is not
possible. The devices are on the motherboard and are hard wired to
specific inputs on the PIC. You cannot change them at all.

For clarity, the only way you can change IRQs in a desktop machine is
to move PCI cards from slot to slot. The slots are hard wired, but the
cards are movable.

I haven't read the whole thread. It got sort of long. While Lee's
comment about interrupt priorities was technically correct, in the old
days where ISR's could (and did) block lower priority interrupts this
was an issue. It is not such an issue today, at least for Linux

As for your laptop, if it is a modern machine is possibly has an APIC.
(Advanced PIC) If it does then enabling it in your kernel and using it
would allow you to change priorities of each hardware device. I
suppose the Fedora kernel has this and that possibly your motherboard
does not, but finding more info on that might lead you to improved
results down the road.

Good luck with whatever you do.


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