[tulip] Adaptec ANA-6944A/TX

Erik Heinz erik@iks-jena.de
Thu Nov 8 09:07:00 2001

On Tue, Nov 06, 2001 at 05:52:18PM -0500, Donald Becker wrote:

> With 2.2 and before, on x86 only, the driver itself hacks the IRQ
> mapping to work around the common BIOS IRQ mapping bug where PCI chips
> behind a bus bridge are assigned different IRQs, but the 4 port card is
> interrupting only on INTA, a single IRQ line.
> With 2.4 the PCI subsystem controls the IRQ mapping, and fixes up this
> common x86 bug.  You can tell that this case has the fix-up implemented
> because IRQ is the same on all interfaces. 

Unfortunately this seems to fail on 4-port cards with 21x5x PCI bridge
chips. I have several of them and neither one works under Linux-2.4.

The picture is always the same: PCI assigns different IRQs to the
different ports. The tulip driver tries to set all IRQs to that of the first
port and therefore reports equal IRQs. This is wrong, however, since
'ifconfig' clearly shows that the PCI-assigned IRQs are actually used.
Trying to bring up more than the first interface sooner or later locks the

I have tried to change the PCI-assigned settings somehow - using 'setpci'
or BIOS settings, but without avail.

| Erik Heinz, IKS GmbH Jena * erik@iks-jena.de * privat: erik@jena.thur.de  |