Subtle PCI weirdness

[gregory.menke at gsfc.nasa.gov]

 > Chris Caudle writes:
 >  > > The 3com docs indicate the board only does 4 byte dma- 
 >  > > though the card is a 64 bit unit, its plugged 
 >  > > into the backplane via a 32 bit connector. 
 >  > 
 >  > Check REQ64#, ACK64#, and the byte enable signals (C/BE# 4-7) to
 >  > see if either the card or bridge is getting confused about whether
 >  > the transactions are 64 bit or 32 bit.  It almost sounds like one
 >  > of the bridges is getting confused about how to translate between
 >  > 32 bit and 64 bit devices.
 >  > 
 >  > -- Chris Caudle
 > 
 > I suspect something like that because the connectors we're using are
 > something of a kludge- the person who procured these boards didn't
 > specify cpci, so we got PCI cards instead- then someone ELSE ordered a
 > set of pci card to cpci connector adaptors (these are 32 bits), which
 > themselves are connected onto a 64 bit capable cpci extender board.
 > Its all rather horrific looking but works well enough to talk to the
 > boards.
 > 
 > I'm switching over to a mtx603 which has a 64 bit pci slot and will
 > continue working there.
 > 

That was the problem.  The dma works fine in the mtx603.  wacky...

Gregm