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    SubjectRe: [PATCH v2 1/7] driver core: emit uevents when device is bound to a driver
    On Wed, Jul 19, 2017 at 5:24 PM, Dmitry Torokhov
    <dmitry.torokhov@gmail.com> wrote:
    > There are certain touch controllers that may come up in either normal
    > (application) or boot mode, depending on whether firmware/configuration is
    > corrupted when they are powered on. In boot mode the kernel does not create
    > input device instance (because it does not necessarily know the
    > characteristics of the input device in question).
    >
    > Another number of controllers does not store firmware in a non-volatile
    > memory, and they similarly need to have firmware loaded before input device
    > instance is created. There are also other types of devices with similar
    > behavior.
    >
    > There is a desire to be able to trigger firmware loading via udev, but it
    > has to happen only when driver is bound to a physical device (i2c or spi).
    > These udev actions can not use ADD events, as those happen too early, so we
    > are introducing BIND and UNBIND events that are emitted at the right
    > moment.
    >
    > Also, many drivers create additional driver-specific device attributes
    > when binding to the device, to provide userspace with additional controls.
    > The new events allow userspace to adjust these driver-specific attributes
    > without worrying that they are not there yet.
    >
    > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

    Hi Dmitry,

    Mike (cc'd) reports a regression with this change:

    ---

    Previously, if I did:

    # rmmod hfi1

    The driver would be removed.

    With 4.14.0-rc2+, when I remove the driver, the PCI bus is
    automatically re-probed and the driver re-loaded.

    ---

    A bisect points to commit 1455cf8dbfd0 "driver core: emit uevents when
    device is bound to a driver". I'm sending this because I have this
    mail in my archive, but I'll let Mike follow up with any other
    details.

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