Re: [PARPORT] figuring out an ECP port problem

From: Bret Comstock Waldow (bwaldow@alum.mit.edu)
Date: Thu May 01 2003 - 09:51:09 EDT

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    On Thu, 2003-05-01 at 04:32, Tim Waugh wrote:
    > On Wed, Apr 30, 2003 at 09:26:03PM -0400, Bret Comstock Waldow wrote:
    >
    > > [bret@ganesha learning]$ cat /proc/sys/dev/parport/parport0/modes
    > > PCSPP,TRISTATE
    > >
    > > The first three settings correspond to the settings in the BIOS. I'm
    > > not sure about the last.
    >
    > As the documentation will tell you, 'modes' indicates the modes that
    > the kernel is willing to use for transfers; in particular, it is NOT
    > just 'what the BIOS can do'. For example, the BIOS may have ECP
    > support, but the kernel may be compiled without support for hardware
    > ECP.

    What documentation are you referring to? VMware's doc's don't address
    this (that I've found). Are you referring to kernel docs in my Linux
    source, docs on the web, and which topic, please? (I'm just getting
    into this, although I'm hoping to learn enough to reverse engineer
    support for a couple of obsolete parallel devices I have.)

    If you are referring to the documentation at the URL, I'm reading that,
    thanks.

    > > Should the response for ECP be PCSPP,TRISTATE,ECP? It's not, and VMware
    > > reports on start-up that the parallel port doesn't support ECP mode and
    > > won't be used.
    >
    > VMware checks the BIOS, not the parport 'modes' file, since it uses
    > direct inb/outb calls not the kernel for its parallel port transfers.
    > If it is still checking the 'modes' file then it is a bug. Perhaps
    > you have an old version of VMware?

    I do. I'm using VMware Express (version 2 for Windows 95 or 98 only).
    I don't know if VMware is checking the modes, I only have gotten far
    enough to see the mode isn't properly reported (I think).

    A fellow, Petr Vandrovic, is writing patches to allow use of early
    versions of VMware with current kernels, and I'm using his patch. I'm
    unemployed, and can't afford the $300 for a current copy of VMware.

    If I can get these device drivers written, I'll be on my way to ditching
    Window$ entirely.

    > http://cyberelk.net/tim/parport/modes.html

    Thanks for the info. I'm currently using the stock Red Hat 9 kernel.
    I'll look to see what options are enabled.

    Cheers,
    Bret

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