Re: [PARPORT] ioctl(parport, PPCLAIM) hangs?

From: Tim Waugh (
Date: Fri Apr 25 2003 - 08:13:59 EDT

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    On Thu, Apr 24, 2003 at 12:41:03PM -0500, Bob Tanner wrote:

    > I switch the BIOS to EPP 1.9 mode, now the following code hangs.
    > int parport = open("/dev/parport0", O_RDWR|O_NOCTTY);
    > ioctl(parport, PPCLAIM); <-- hangs
    > Why would the ioctl() hang when I try to claim the port?

    Because some other driver has the port already and isn't letting it
    go. It's also a badly-behaved driver, since if it isn't going to let
    go of the port it ought to have asked for exclusive access in the
    first place (in which case the open would have failed I think).

    It might be the lp driver: in interrupt-driven mode it doesn't behave
    nicely like it should.

    Find out: /proc/sys/dev/parport/parport0/devices/active


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