Re: [PARPORT] Printing unreliable using ECP/EPP

From: Dave Strauss (
Date: Thu Dec 11 2003 - 10:08:42 EST

  • Next message: Neil Munro: "RE: [PARPORT] Printing unreliable using ECP/EPP"

    I don't know if things have changed much since RH 7.3, but as I look
    at my one machine with RH 9 installed it looks like they haven't. RH
    typically does not ship with ECP mode enabled in the parport driver,
    so if you want better performance you'll have to rebuild your modules
    to take advantage of it. I can send you instructions for doing that if
    you need them, but basically under parallel port support you want to
    enable FIFO/DMA support, rebuild and install your modules, then
    enable FIFO support in /etc/modules.conf by adding one of the following
    two lines:

    options parport_pc irq=auto dma=none
    options parport_pc irq=auto dma=auto

    The first line sets up polled I/O to do transfers, while the second
    line sets up DMA. Experiments I did a couple of years ago showed that
    polled I/O is faster overall but burdens the CPU more than DMA.

    This *may* fix your problem, but it's strange that your machine
    becomes "unusable" while printing -- even with "standard" (a.k.a
    compatibility) mode it shouldn't be doing this.

    I'm sure Tim Waugh will correct me if I'm wrong about RH 9.

    -- Dave Strauss

    On Thu, 11 Dec 2003 13:58:45 -0000, "Neil Munro" <> wrote:
    > Hardware: Asus P4S533 Mainboard + Epson Stylus Colour 480
    > Software: Red Hat 9 using CUPS set up using Red Hat printer configuration.
    > When I select ECP or EPP mode in the BIOS, it works but after perhaps 10-20%
    > of a page of graphics (black or colour), it does an eject page and starts
    > printing the remainder on another page, repeating this every 10-20%. It
    > seems OK with plain text, but this may just be because there is less data,
    > so statistically less chance. The error is repeatable, I never get a full
    > page printed.
    > Switching the Parallel Port to Standard mode in the BIOS fixes this, so I
    > don't think it is a problem with the printer driver.
    > As a secondary question, is there any setting to place parport on a lower
    > priority so it doesn't tie up the PC so much while it is printing? I'm not
    > bothered if it prints slowly, just reliably and without making the PC
    > un-useable during printing. If I could do this, I could live with using
    > Standard mode!
    > Thanks.
    > Neil.
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