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    SubjectRe: [PATCH] [PNP] 'modalias' sysfs export
    Kay Sievers wrote:
    > On Mon, Feb 27, 2006 at 10:40:19PM +0100, Pierre Ossman wrote:
    >> User space hardware detection need the 'modalias' attributes in the
    >> sysfs tree. This patch adds support to the PNP bus.
    >
    >> +
    >> + /* FIXME: modalias can only do one alias */
    >> + return sprintf(buf, "pnp:c%s\n", pos->id);
    >
    > Without the FIXME actually "fixed", this does not make sense. You want to
    > match always on _all_ aliases. In most cases where you have more than
    > one, the first one is the vendor specific one which isn't interesting at
    > all on Linux. If you have more than one entry usually the second one is the
    > one you are looking for.
    >
    > So eighter we find a way to encode _all_ id's in one modalias string which can
    > be matched by a wildcard or keep the current solution which iterates over the
    > sysfs "id" file and calls modprobe for every entry.
    >

    That's a bit harsh. Although the FIXME is a downer, this patch is a
    strict addition of functionality, not removal. It solves a real problem
    for me, and it does so without removing any functionality for anyone
    else. The fact is that most PNP devices do not have multiple id:s (at
    least the ACPI variant which is the most common in todays machines), so
    the problem is not near as big as you make it out to be.

    That said, I agree that it would be desirable to fix this. First of all
    we would need to synchronise this with userspace. Currently I guess that
    means udev. Allowing 'modalias' to contain multiple lines should be a
    simple enough solution (provided we don't fill the available buffer space).

    The PNP cards are also a bit of a problem, but this isn't something new.
    When matching a device to a driver, the card ID must match and also all
    device ID:s. The problem is that the device ID:s are sets, not lists.
    I.e. we compare the unordered contents of the two, with no regard to
    ordering.

    Rgds
    Pierre

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