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

From: Philip Blundell (
Date: Thu Aug 16 2001 - 13:24:48 EDT

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

    >Second problem: the original patch leaves the parallel port in ECP
    >mode permanently. My experience with working on printers of various
    >sorts is that this is in general a Bad Thing; the 1284 protocol is
    >easily broken if either side gets out of sync with the other, and the
    >longer the port is left in ECP mode the easier it is for this to
    >happen. Also, if other drivers want to use the port in other modes
    >(or in other ways) this could cause problems.

    I guess maybe switching back to compatibility mode on close might be the right
    thing to do. Flipping into and out of ECP mode on every write seems like a
    bit too much of an overhead. Other drivers wanting to change the mode of the
    port shouldn't cause a problem, I don't think: they can negotiate to whatever
    mode they want, and parport_write will reselect its favourite next time it's

    As to your other three issues, I'm not sure what to make of those. I got the
    same low data rate as you, but I don't know why.

    Does anybody know how other operating systems handle retrieving "ready" status
    when using ECP mode?


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