[SGVLUG] More laptop fun--IRQ assignments

[Michael Proctor-Smith]

On 11/26/05, Dustin <laurence at alice.caltech.edu> wrote:
> Heh, I'm having all sorts of fun hitting problems from a new angle.  I've
> seen occasional dropped packets, which could very be ISP wierdness but
> didn't seem to affect the desktop going over the same DSL modem.  So I
> took a quick look and found that video, audio, ethernet, and one of the
> USB hubs were all on IRQ 11.
>
> Regardless of whether that was the problem (and now that I think of it I
> might have gotten unlucky and plugged the webcam into the one USB port
> that was on that IRQ), I'd like to be able to reassign IRQs.  I do plan to
> record with the laptop and would like the ability to put the soundcard by
> itself at a high priority.
>
> Funny thing about laptops, though: the BIOS appears intentionally crippled
> and omits critical capability...like the ability to manually assign IRQs.
> (Gee, nobody ever needed to do that, right?)  I guess I've never really
> seen how to reassign IRQs in the OS itself, so I'm in new territory again.
> Some research suggests that reassigning IRQs may be possible but didn't
> turn up anything more definite than the existence of an obsolete and
> unmaintained patch to the APIC kernel code that actually sets up the
> vector.  I did build an APIC kernel which works fine, but doesn't solve
> the conflict--it just moves the overloaded IRQ to #16.
>
> I'll probably have to take this to the Linux Audio Users list, since
> that's the biggest concentration of people who regularly fiddle with this
> stuff, but maybe someone here already knows how to reassign IRQs in
> software.

This is normal for the last five years or so. All those things are on
IRQ 10 on my laptop. Modern hardware really does not have a problem
with sharing IRQs.