[olug] eth0 question

tetherow at nol.org tetherow at nol.org
Tue Aug 28 20:43:10 UTC 2001

Jon is correct on the pci PNP, the irq's are set by bios at power up
not OS load.  If you have having conflicts with your IRQs on pci plug
and play card the easiest way I have found is move the pci cards
around.  It seems like a cheesy answer but it has worked for me every
time I have run into a problem.  The irq's are assigned in a
predetermined order on the board (usually slot 1 through slot N but I
haven't seen anything to back that up).  The other option you have is
to turn off PNP on the card and figure out what settings to use when you
load the module (or pass as kernel parameters if built into the kernel).

lspci -v found in pciutils (atleast under debian) will report the irq
and address information PCI cards and sometimes the bios will report it
at boot time.  You can also pull the same information by 'cat /proc/pci'

Some cards come with tools to set the various settings in DOS or
windows (3Com being most prominent) but of course this requires dual
boot or wine/dosemu installation.

If you cannot change the IRQ on the card and you are still running into
a conflict another approach is to move the IRQ for the card out of the
PNP assignable block in bios.

On 28 Aug, Jon wrote:
> I am no kernel hacker but here goes.
> isa pnp is not anything like pci plug and play.  I don't think you can manually configure a pci card. it isn't an option.   older isa cards gave you the option.  You could configure the card so it didn't conflict or you could run in in a plug and play mode where the bios would assign its values.  kernels in the 2.2 series required quite a bit to set these values.  you had to do a pnpdump of the isa bus and configure a startup file identifying hardware and irqs and io ranges. It stunk.  recently I changed my soundcard back to a headache free sb awe64 and found that the 2.4 kernel has greatly improved its pnp support.  It was as easy as with a pci device.  I have ran net cards with pnp disabled cause that is what I had to do to get them working.  I have a feeling that 2.4 might handle them fine. but who knows.
> -Jon

Sam Tetherow                           tetherow at nol.org
Director of Development
NIC Labs (IDG)                         http://www.nicusa.com


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