Re: Shared Interrupts for PCI Devices

[Bruce Smith <bruce@xxxxxxxxxxx>]

> I was wondering if anyone might have suggestions for Shared Interrupts
> for PCI devices in Linux. I have a STB AGP video card(RIVA 128) that I
> could not get to work with XWindow. I downloaded some drivers from SuSE
> for it and my screen still went black when I started XWindow. I assumed
> it must be some kind of hardware conflict so I checked interrupts and
> found my Intel PCI EtherCard used IRQ 11 which it shared with the video
> card bus slot. I moved the Intel card to a different slot which I
> noticed it then used IRQ 9 and my video card functioned fine with
> XWindow. Both these cards worked fine together on IRQ 11 in Windows 98.
> Is there a "general rule" for using shared interrupts with PCI devices
> under Linux? I have a 64 bit PCI sound blaster that I could not get to
> work and I now suspect that it might be the same problem. Do I need to
> re-configure my CMOS settings differently? Is there a way to check
> hardware interrupts or set them in Linux?(I've been checking the device
> manager in Windows 98 for interrupt info.)

The only way I've ever heard of to share IRQ's in Linux is to compile
a kernel with both items to be shared as modules, and then manually
unload/load the modules as needed, but never have them both loaded at
the same time.  This means you cannot have both devices active at the 
same time.  I don't know if that would work for your situation or not.

As far as checking IRQ settings, you can do a "cat /proc/interrupts"
but it does not display all of the interrupts for some reason.

--------------------------------------------
Bruce Smith                bruce@armintl.com
System Administrator / Network Administrator
Armstrong International, Inc.
Three Rivers, Michigan  49093  USA
http://www.armstrong-intl.com/
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