[PARPORT] Re: DMA channel configuration

From: Tim Waugh (twaugh@redhat.com)
Date: Mon Mar 20 2000 - 16:49:29 EST

  • Next message: Chandan Mishra: "[PARPORT] DMA channel configuration"

    On Mon, 20 Mar 2000, Chandan Mishra wrote:

    > I have a question which is not parallel port specific but arose during
    > the time while I was playing with parport driver. On PC how is the dma
    > channel autoconfigured if it is. As my understanding goes each
    > peripherical controller is kind of hard wired to a particular dma
    > channel of a dma controller (corect me if I am wrong). Then how does
    > auto configuration works or how odes the driver discover the dma
    > channel to use. Also how does peripheral auto-finds the available
    > irqs.

    For parallel ports: ECP chipsets just tell you this information. You ask
    the chipset what DMA channel and IRQ line it's using, and it tells you.
    It's theoretically possible to program it to use a DMA channel and IRQ
    line of your choice, but I've never seen an implementation that allows

    For IRQs, see probe_irq_on and probe_irq_off.


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