[PARPORT] Re: [PATCH] to drivers/parport/ieee1284_ops.c to fix timing dependent hang

From: Tim Josling (tej@melbpc.org.au)
Date: Sat Mar 22 2003 - 15:31:50 EST

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    Jeremy Fitzhardinge wrote:
    > On Sat, 2003-03-22 at 01:23, Tim Josling wrote:
    >>According to my reading of the code, it should only happen in polled
    >>mode, but I have only one week of experience looking at kernel source.
    > I'm wondering if a better fix might be to have something like:
    > if (wait * 2 > wait)
    > wait *= 2;
    > at the bottom of the loop, so that the wrap-around doesn't happen.

    I tried
      wait *=2;
            if (wait > 10 * HZ)
                    wait = 10 * HZ;
    and that worked, so your theory would probably work. However to my mind
    it is a hack.

    >>So it should be a work-around, assuming interrupts work on the parallel
    >>port on your system :-). It is an very vexing problem, as I'm sure you know.
    >>By the way, LJ1100s tend to get page feeding problems about the time the
    >>warranty runs out, but HP has a free kit you can order to fix the problem.
    > Yes, I just installed it. It suddenly made the printer useful again, so
    > I've printing more, and seeing the hangs. I enabled interrupts, which
    > seems to work OK.
    > J

    Good. That (enabling interrupts fixes the problem) tends to add credence
    to my theory.

    Happy printing!

    Tim Josling

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