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

From: Tim Waugh (
Date: Thu Aug 16 2001 - 17:30:14 EDT

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

    On Thu, Aug 16, 2001 at 02:20:47PM -0400, Dave Strauss wrote:

    > This would effectively lock any other drivers out from using
    > parport; is this a Bad Thing?

    It's impolite, yes. Actually lp already does this in some
    circumstances: when it is interrupt driven and waiting for the printer
    to become ready, it leaves the port claimed. I was going to look into
    changing this so that it yielded it once a second or so.

    > BTW, as far as I can tell Windows printer drivers effectively do this;
    > they claim the parallel port for the duration of the data transfer and
    > so are able to be somewhat more efficient in how and when they
    > negotiate to ECP mode.


    > I believe that as long as the channel is in ECP mode the peripheral is
    > essentially always "ready". The host is always allowed to try to send
    > a byte to the peripheral and the only thing the peripheral can do is
    > not read it.

    That's my interpretation too.


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