Subject: Re: Dell GXPro configuration
To: Scott Presnell <srp@zgi.com>
From: Chris G. Demetriou <cgd@sibyte.com>
List: port-i386
Date: 08/27/2000 22:13:57
[ from your description, you probably have the same kind of dell i do. 8-]

srp@zgi.com (Scott Presnell) writes:
> Regarding the fact that the USB and the ethernet devices
> are both assigned irq 11 is this:
> 
> 	a) an error. 
> 
> 	b) a feature of having two PCI busses, as interrupts are
> unique per bus.
> 
> 	c) something else altogether?

some combination of B and C.

PCI interrupts are level-triggered.  It's OK (albeit with some minor
performance loss) to share them between two devices.


I could provide you some more detail about why they might be shared,
but in a nutshell it's OK, and normal on most PCs.

for more info, you might investigate how PCs route PCI IRQs (don't
have any good references for this, i just understand it at this point
8-), and the PCI-PCI bridge spec.



cgd