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    SubjectRe: [PATCH] Input: serio - clear serio event queue after sysfs driver rebind
    On Sat, Nov 27, 2010 at 12:41 AM, Dmitry Torokhov
    <dmitry.torokhov@gmail.com> wrote:
    > Hi Duncan,
    >
    > On Mon, Nov 22, 2010 at 03:09:50PM -0800, Duncan Laurie wrote:
    >> When rebinding a serio driver via sysfs drvctl interface it is possible for
    >> an interrupt to trigger after the disconnect of the existing driver and
    >> before the binding of the new driver.  This will cause the serio interrupt
    >> handler to queue a rescan event which will disconnect the new driver
    >> immediately after it is attached.
    >>
    >> This change clears the serio event queue after processing the drvctl
    >> request but before releasing the serio mutex, which will clear any queued
    >> rescans before they can get processed.
    >>
    >> Reproduction involves issuing a rebind of device port from psmouse driver
    >> to serio_raw driver while generating input to trigger interrupts.  Then
    >> checking to see if the corresponding i8042/serio4/driver is correctly
    >> attached to the serio_raw driver instead of psmouse.
    >>
    >> Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
    >> ---
    >>  drivers/input/serio/serio.c |    1 +
    >>  1 files changed, 1 insertions(+), 0 deletions(-)
    >>
    >> diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
    >> index 405bf21..a66307e 100644
    >> --- a/drivers/input/serio/serio.c
    >> +++ b/drivers/input/serio/serio.c
    >> @@ -454,6 +454,7 @@ static ssize_t serio_rebind_driver(struct device *dev, struct device_attribute *
    >>               serio_disconnect_port(serio);
    >>               error = serio_bind_driver(serio, to_serio_driver(drv));
    >>               put_driver(drv);
    >> +             serio_remove_pending_events(serio);
    >
    > Hmm, makes sense, although should we limit events being removed to
    > rescan events only?
    >


    That seems reasonable. It would mean adding a new function or a
    parameter to the existing serio_remove_pending_events function, do you
    have a preference?

    Thanks,
    -duncan
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