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

From: Tim Waugh (
Date: Thu Aug 23 2001 - 11:08:55 EDT

  • Next message: Dave Strauss: "Re: [PARPORT] ECP mode transfers in 2.4.x kernels"

    On Thu, Aug 23, 2001 at 10:07:28AM -0400, Dave Strauss wrote:

    > This may or may not help, depending on how big the chunks are that get
    > passed into lp. If the application is sending things in small pieces,
    > increasing LP_BUFFER_SIZE isn't going to help much.

    Right, and a quick test shows that LPRng (for example) likes to write
    one page at a time. :-(

    > Do you mean the "preempt" in the parport device structure? So, lp
    > would claim parport on lp_open(), put it into ecp mode, and leave it
    > both claimed and in ecp mode until lp_release(). Is that what you
    > mean? One problem -- can't the preempt function get called at any
    > time? What if it gets called in the middle of a data transfer (or in
    > the middle of any other lp entrypoint, for that matter)?

    The preempt function doesn't have to give up the port right away. It
    can make a note that it should release it 'soon'. Then at the end of
    the entry points, you can check the flag and release the port if


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