use the kernel to change an irq?

use the kernel to change an irq?

[Jacob Luna Lundberg]

Oh Great Gurus:

I have an agp video card that seems quite picky about interrupts, and a
bios that is insisting on sharing the video card's interrupt with whatever
is in the first pci slot.  So my question is, is there any way for the
kernel to more or less say ``screw you'' to the bios and pick the irq for
the video card itself?  I have a spare irq I'd love for it to use...

Oh, almost forgot:  Yes, I'd just vacate the pci slot below the video
card, but sadly all my pci slots are in use.  :(

Ok, I'll admit the card is an nVidia card and I'm trying to use the (evil)
binary drivers.  But note I'm *not* asking for help with that directly.
I'm merely asking if there's a way to avoid sharing the interrupt...

Thanks Muchly,
-Jacob

-- 

The authoritarian attitude has to be fought wherever
you find it, lest it smother you and other hackers.

 - Eric S. Raymond

Re: use the kernel to change an irq?

[Jeffrey Ingber]

Jacob Luna Lundberg wrote:
> 
> Oh Great Gurus:
> 
> I have an agp video card that seems quite picky about interrupts, and a
> bios that is insisting on sharing the video card's interrupt with whatever
> is in the first pci slot.  So my question is, is there any way for the

Your problem is most likely _not_ an IRQ issue, but a bus mastering
issue.  Your AGP and PCI most likely share the same busmastering line. 
The IRQ should not be an issue.

-- 
Jeffrey H. Ingber (jhingber _at_ ix.netcom.com)

"Windows 95 is a 32-bit shell for a 16-bit extension to an 
8-bit  operating system designed for a 4-bit microprocessor
 by a 2-bit company that can't stand one bit of competition."

Re: use the kernel to change an irq?

[Tim Wright]

They're sharing an IRQ because they're attached to the same interrupt line
on the motherboard. Nothing you can do in software is ever going to change
this. For most BX chipset motherboards I've seen, the AGP slot shares the
same interrupt as the first (i.e. physically closest) PCI slot. If you change
the IRQ for one, you just changed it for the other. If you don't want it to
share, you can't have anything in the other slot. Sounds like you're out of
luck :-(

Tim

On Thu, Mar 22, 2001 at 11:10:28PM -0800, Jacob Luna Lundberg wrote:
> 
> Oh Great Gurus:
> 
> I have an agp video card that seems quite picky about interrupts, and a
> bios that is insisting on sharing the video card's interrupt with whatever
> is in the first pci slot.  So my question is, is there any way for the
> kernel to more or less say ``screw you'' to the bios and pick the irq for
> the video card itself?  I have a spare irq I'd love for it to use...
> 
> Oh, almost forgot:  Yes, I'd just vacate the pci slot below the video
> card, but sadly all my pci slots are in use.  :(
> 
> Ok, I'll admit the card is an nVidia card and I'm trying to use the (evil)
> binary drivers.  But note I'm *not* asking for help with that directly.
> I'm merely asking if there's a way to avoid sharing the interrupt...
> 
> Thanks Muchly,
> -Jacob
> 

-- 
Tim Wright - timw@splhi.com or timw@aracnet.com or twright@us.ibm.com
IBM Linux Technology Center, Beaverton, Oregon
Interested in Linux scalability ? Look at http://lse.sourceforge.net/
"Nobody ever said I was charming, they said "Rimmer, you're a git!"" RD VI