Re: udev sysfs docs Re: State of devfs in 2.6?

From: Matthew Reppert (repp0017_at_tc.umn.edu)
Date: 12/09/03

  • Next message: H. Peter Anvin: "Re: const versus __attribute__((const))" 
    To: Bob <recbo@nishanet.com>
Date:	Tue, 09 Dec 2003 01:39:56 -0600

    On Tue, 2003-12-09 at 01:21, Bob wrote:
    > Witukind wrote:
    >
    > >From the udev FAQ:
    > >
    > >Q: But udev will not automatically load a driver if a /dev node is opened
    > > when it is not present like devfs will do.
    > >A: If you really require this functionality, then use devfs. It is still
    > > present in the kernel.
    > >
    > >Will it have this 'equivalent functionality' some day?
    > >
    > >
    > >
    > >
    > Shouldn't hotplug handle it?

    How would hotplug handle it?

    Or, more directly ... on my system, /dev is just a normal directory
    on an ext2 filesystem. If something tries to open a file on it that
    doesn't exist, open will just return ENOENT. How is open supposed to
    know that someone is trying to open a device node? The naive solution
    is to conditionally check for the presence of "/dev" at the beginning
    of all requested filenames that don't exist, which strikes me as ...
    well, not necessarily a good idea. (I can't really say why beyond gut
    feeling.)

    My guess is, unfortunately, udev probably won't handle this any time
    soon. (Or, if it does, through some possibly clever mechanism that, as
    someone unfamiliar with the relevant bits of the system, I can't see.)
    I'd be interested in a solution to this, mostly out of curiosity since
    it seems like it might be interesting, but I don't see a nice one coming
    easily. I wouldn't mind someone more clueful telling me I'm wrong,
    though. At the least, it means more people being receptive to moving
    to udev.

    Matt

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  • Next message: H. Peter Anvin: "Re: const versus __attribute__((const))"

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