Re: [PARPORT] ECP mode transfers in 2.4.x kernels

From: Dave Strauss (
Date: Tue Sep 11 2001 - 17:49:57 EDT

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    On Mon, 10 Sep 2001 22:37:32 +0100, Philip Blundell <> wrote:
    > >I think at least for now I think I'm just going to turn DMA off. I'm
    > >still open to trying other experiments, though, if anybody wants to
    > >suggest something.
    > I guess it would be instructive to know how the corruptions
    > correspond to invocations of parport_pc_fifo_write_block_dma. If
    > you feel like hacking that function around a bit, how about adding
    > a flag that gets set when the "DMA write timed out" condition
    > happens; if the flag is set on entry to the function, dump out the
    > first few bytes in `buf' to the console and clear the flag again.
    > I'm slightly suspicious that there might be a hardware flaw in
    > either your DMA controller or your parallel port. If you have
    > another computer with a different chipset available, it would be
    > interesting to know whether you can make the same thing happen.
    > p.

    I'm also slightly suspicious of the hardware, but unfortunately
    I've only got the one machine that has DMA and is running a 2.4.x
    kernel. The only other 2.4.x machine I have access to at the
    moment doesn't have DMA.

    I'll try the buf dump when I get a chance.

    -- Dave Strauss

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