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    SubjectRe: Migrating to larger numbers
    Stephen Frost writes:
    > Hmm, I think maybe the question is, which way is it driven?
    > Does the kernel automagically load the driver when the device is
    > detected, or does the user attempt to access a device, which the kernel
    > then has to go out and see if it exists (And if it can load a module
    > for it). I've seen it both ways.
    > If the kernel detects it, then having a user-space daemon
    > running that handles the modprobe or whatnot and the creation of the
    > devices will work (pcmcia seems to work in this way). However, what
    > about devices that exist at all times in a system, but are compiled by
    > the user as modules to perhaps save memory? Or the issue with printers
    > and zip drives, where IIRC the user can rmmod and insmod the appropriate
    > modules depending on which device he wants to talk to.
    > I don't know if devfs handles all of these or not, I'm just
    > trying to bring up points where it would be nice to have something that
    > handles these different situations, and handles them in One way (if at
    > all possible) to make it easier for the user.

    Devfs handles it both ways. In the former case, a device driver
    registers device entries with devfs. So that can happen in response to
    a device plug/unplug event, and doesn't even need interaction from
    user space.

    In the latter case, an attempt to access a device node for which there
    is no loaded driver (and thus no entry in devfs) generates a module
    load. That module load will in turn result in the appropriate device
    entry being registered and magically appearing. So it all just works.



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