HELP: EM bus_alloc_resource_any fails on Dell Dimension 9150

David Christensen davidch at
Mon Jun 18 22:13:22 UTC 2007

> I have a problem that I've never seen before, and although 
> I've poked at
> it a bit I'm kinda stuck. Anyone more knowledgable than I in the bus
> code care to offer suggestions?
> Here's the situation: Dell Dimension 9150, you put in a PCI-E 4 port
> E1000 adapters... ya I know this makes it a configuration unlikely
> to be used :)... and besides that works fine... The problem arises
> when you ALSO stick in an 82541_GI, which is just PCI...
> When you load the em driver it attaches the 4 ports just fine, but
> then the lowly 541 fails bus_alloc_resource_any() of the IO PORT.
> It isnt the code, if you remove the 4 port card the 541 will  attach
> and work without a whimper.
> So, there's something happening in PCI space and its resources
> here that the current em driver is not equipped to handle, and I
> would really like to understand what it is.
> Suggestions to help me debug this?

How much I/O space does each adapter require?  PCI specification seems
to limit I/O space to 256 bytes per function.  How much I/O space is 
the upstream PCIe switch configured to support?  Are there any other
I/O devices downstream from the same PCIe switch?  If you disable a
single function on the quad-port device does the allocation work?
What does "pciconf -lv" return on the system?


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