Re: [PARPORT] Beginner needs help with EPP...

From: Bob Tanner (tanner@real-time.com)
Date: Mon Apr 21 2003 - 16:15:22 EDT

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    On Sunday 20 April 2003 07:08 pm, Sven Heithecker wrote:
    > Hi,
    >
    > I am currently new to parport/EPP programming and need some startup-help.
    > I need to access the PC's parport in EPP mode. It's going to be a "static"
    > solution, so no drivers etc are needed, just plain access to the port.
    > Currently I am trying something like
    >
    > int mode = IEEE1284_MODE_EPP;
    > if( (fd_par = open("/dev/parport0",O_RDWR)) == -1 ) error(...)
    > if(ioctl(fd_par,PPCLAIM)) error(...)
    > if(ioctl(fd_par,PPNEGOT,&mode)) error(...)
    >
    > and then simple access using read(fd_par,...) and write(fd_per,...).
    > However, so far the program stopps at the EPP negotiation with an I/O
    > error. I activated EPP in the BIOS, but when looking at
    > /proc/sys/dev/parport0, it say that no IRQ or DMA channels are assigned and
    > that EPP is not possible.

    Try turning on debugging in the parport module?

    I'm not sure if this is the proper way, but I edited:

    ieee1284_ops.c
    ieee1284.c
    parport_pc.c

    And changed the #undef DEBUG to #define DEBUG

    And I hardcoded static int verbose_probing = 1 into parport_pc.c:97

    I have the parallel port stuff compiled into, but if you are doing modules I
    believe you can do something like this in your /etc/modules.conf:

    alias parport_lowlevel parport_pc verbose_probing=1

    Or modprobe parport_pc verbose_probing=1 

    -- 
Bob Tanner <tanner@real-time.com>         | Phone : (952)943-8700
http://www.mn-linux.org, Minnesota, Linux | Fax   : (952)943-8500
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