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    SubjectRe: [PATCH 2.6.23] ibmebus: Prevent bus_id collisions
    Hi Joachim-

    Joachim Fenkes wrote:
    > Nathan Lynch <> wrote on 29.08.2007 20:12:32:
    > > Will anything break?
    > Nope. Userspace programs should not depend on ibmebus' way of naming the
    > devices; especially since some overly long loc_codes tended to be
    > truncated and thus rendered useless. I have tested IBM's DLPAR tools
    > against the changed kernel, and they didn't break.


    > > Also, I dislike this approach of duplicating the firmware device tree
    > > path in sysfs.
    > Why? Any specific reasons for your dislike?

    struct device's bus_id field is but 20 bytes in size. Too close for

    > > Are GX/ibmebus devices guaranteed to be children of
    > > the same node in the OF device tree? If so, their unit addresses will
    > > be unique, and therefore suitable values for bus_id. I believe this
    > > is what the powerpc vio bus code does.
    > While there's no such guarantee (as in "officially signed document"), yes,
    > I expect future GX devices to also appear beneath the OFDT root node. For
    > the existing devices, the unit addresses are already part of the device
    > name, so I save the need to use sprintf() again. Plus, I rather like using
    > the full_name since it also contains a descriptive name as opposed to
    > being just nondescript numbers, helping the layman (ie user) to make sense
    > out of a dev_id.

    Okay, but your layman isn't supposed to be relying on any
    user-friendly properties of the name :) Hope he doesn't work on a
    distro installer.

    Anyway, if you're still confident in this approach, I relent. :)
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      Last update: 2007-08-30 19:59    [W:0.022 / U:34.540 seconds]
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