[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: DMA channels with PCI devices




AIX is not my OS either, but PCI devices typically have DMA controllers
built into them and don't use DMA channels in the ISA sense. Most (all?)
PCI interface chips on the market have at least 2 DMA controllers built
in.

Arbitration in PCI is not a DMA thing but a master control thing. The
motherboard does arbitration by granting the bus to devices that want
to be bus masters to perform a transfer. It is hidden from the driver
writer.

-- 
Steve Williams
steve@icarus.com
steve@picturel.com

"The woods are lovely, dark and deep.  But I have promises to keep,
And lines to code before I sleep, And lines to code before I sleep."