Re: [PARPORT] Huge freeze ups with parallel port zip drive (ppa) and kernel 2.2.x

From: Ian David Flintoft (
Date: Thu Oct 26 2000 - 12:56:30 EDT

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    Tim Waugh wrote:
    > Try changing the BIOS settings. Some EPP implementations can caused
    > problems, and most (all?) halt the CPU while they do the transfers.
    > Also, what's the latest 2.2.x kernel you've tried?

    I'm currently using 2.2.17. I've had the same problem with
    all 2.2.x kernels since I started using it - something
    like 2.2.10 I think. I've been using SMP kernels all the
    time - maybe that is worth investigating....

    I've tried setting the BIOS to:

    EPP v1.7 - this doesn't work at all
    EPP v1.9
    Bidirectional = PS/2

    I've also tried using parport with and without irq's.
    None of these seem to cure the problem - it is possible
    that EPP v1.9 is the best of the lot but only slightly.

    It feels like it's the kernel buffering - ~80Mb is
    written into the buffer very quickly. Once this starts
    to flush to disk I have problems with applications getting
    stuck. They only free up very intermittently until all
    the data is written to the disk. Sometimes they don't
    free up until the write is finished.

    It looks like they get stuck waiting for some
    system calls to unblock or access to some other kernel
    resource is freed. For example if I'm using a shell it is usually
    OK unless I use du for example. Netscape won't freeze if I'm
    scrolling around on a loaded page, but if I try to load another
    page there is a good chance it will lock up for quite a while
    - doing the hostname lookup maybe?




    Dr Ian David Flintoft Email: Applied Electromagnetics Group Tel: +44 (0)1904 432391 Department of Electronics Fax: +44 (0)1904 433224 University of York Heslington YORK, UK YO10 5DD Web:

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