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    SubjectRe: Network: convert network devices to use struct device instead of class_device
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    On Thu, 2007-02-08 at 22:59 -0500, Dmitry Torokhov wrote:
    > On Thursday 08 February 2007 19:56, Greg KH wrote:
    > > On Thu, Feb 08, 2007 at 12:29:12PM -0500, Dmitry Torokhov wrote:
    > > > On 2/8/07, Stephen Hemminger <shemminger@linux-foundation.org> wrote:
    > > > >On Thu, 08 Feb 2007 07:43:18 -0500

    > > > >> > Network: convert network devices to use struct device instead of
    > > > >class_device
    > > > >> >
    > > > >> > This lets the network core have the ability to handle
    > > > >suspend/resume
    > > > >> > issues, if it wants to.
    > > > >
    > > > >It fixes a non-problem. I would like to see the network core suspend/resume
    > > > >proposal as well. Last time I examined doing network core suspend help,
    > > > >the problem was that the physical device suspend was called before the
    > > > >class device. It is not clear how this change would help.
    > > >
    > > > If physical devices are registered before class devices then when
    > > > suspending class devices are naturally suspended first. It is still
    > > > not clear to me why we need to convert everythign to struct device, I
    > > > believe I've shown (with patches) that it is possible to integrate
    > > > struct class_device into PM framework and avoid reshuffling half of
    > > > the kernel code.
    > >
    > > I don't want to have two separate device trees in the kernel (well, one
    > > big device tree and a bunch of little class_device trees.) The code
    > > duplication in the class_device code is just too much, and I get
    > > questions all the time as to what the differences are.
    > >
    >
    > While duplication of code is a real concern my worry is constant fattening
    > of struct device. For example most physical devices do not interface
    > directly with userspace but every single one of them now has dev_t.
    > Former class_devices do not need suspend/resume early framework either.
    > And so on, and so forth.

    The dev_t is a good example for the mess we try to fix here. Not having
    a dev_t for "devices" lead to the creation of a lot of otherwise
    completely useless "class devices" which are just a total pain to
    interpret, and follow the events they create, from userspace.

    Things like the scsi_device devices, usb_device devices, ... just exist,
    because only this type of devices was allowed to pass information for
    device nodes to userspace.

    Thanks,
    Kay

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