64-bit pci bus on a powermac g4
Chas Williams
chas at cmf.nrl.navy.mil
Sun Sep 10 04:57:36 EST 2000
i am writing a driver for an atm adapter and i am seeing some strange
problems. the card is 32/64 bit. it works fine in my 32-bit pci bus
on my umax s900, but in the g4 it oops' with a trap 300 during operation.
i understand this to be 'data access exception' or 'data storage exception'.
a couple questions:
. is the 64bit pci bus capability functional in the g4? (i gather it
must be since my 64bit ati rage pro for the second monitor is working fine)
. anyone else written a driver for a 64bit pci card in the g4's?
. do i need to align my dma regions to 64bits? shouldnt the card be
able transfer non-dma until it gets to a dma region? i suppose this
depends on the bridge/card controller. the driver documentation
is a bit lacking on this detail. it claims that tx buffers dont
require special alignment but if you dont use dma, of course it doesnt.
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