Re: [PARPORT] Questions and first pass at ieee1284 MODULE_DEVICE_TABLE support

From: Adam J. Richter (
Date: Wed Dec 13 2000 - 19:26:21 EST

  • Next message: Tim Waugh: "Re: [PARPORT] Questions and first pass at ieee1284 MODULE_DEVICE_TABLE support"

    >On Wed, Dec 13, 2000 at 03:34:07PM -0800, Adam J. Richter wrote:

    Tim Waugh wrote:
    >If we have user-space matching, why have kernel-space matching as

            The user space matching scheme that I described will only
    determine what modules to load. Once the modules are loaded, it is
    up to them to figure out which devices to bind to. Imagine that
    I have a system with three parallel ports, one of which has a
    zip drive attached to it. Once the module is loaded, how does
    it figure out which port to bind to, if it cannot check the
    ieee1284 device string?

            While it would be possible to write more user level code so
    that the modules would be loaded with additional kernel arguments
    telling it what to bind to, there would still need to be a kernel
    based mechanism for the cases where we do want to support hot plugging
    even if we cannot reliably detect it in all cases. I suppose that
    too could be communicated through some new ioctl's, but that raises
    other issues about how a user level program would communicate this
    information to the kernel and how it would be run (e.g., spawned by
    /sbin/hotplug, a persistent daemon, a cron job). At the moment, I
    think the simplest approach is probably to be consistent with the way
    the clients of MODULE_DEVICE_TABLE.

    >I'd say ditch it and deprecate lp=auto.

            This facility would eventually cause lp=auto to be rewritten
    or removed.

    >> Do any devices actually say "CLASS:" in their ID information?

    >Not sure.

            OK. Thanks for the information. Also, are you sure that there
    is a device where a keyword is given in lower case (for example "cls:"
    is used instead of "CLS:")?

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