On Mon, 2010-08-30 at 23:46 -0400, Michael Poole wrote:
> On Mon, 2010-08-30 at 13:20 -0400, Chase Douglas wrote:
> > From: Chase Douglas <chase.douglas@xxxxxxxxxx>
> >
> > The driver listens only for raw events from the device. If we allow
> > the hidinput layer to initialize, we can hit NULL pointer dereferences
> > in the hidinput layer because disconnecting only removes the input
> > devices from the hid device while leaving the hid fields around.
> >
> > Signed-off-by: Chase Douglas <chase.douglas@xxxxxxxxxxxxx>
> > ---
> > drivers/hid/hid-magicmouse.c | 6 ++----
> > 1 files changed, 2 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
> > index ee78787..2d8532d 100644
> > --- a/drivers/hid/hid-magicmouse.c
> > +++ b/drivers/hid/hid-magicmouse.c
> > @@ -404,15 +404,13 @@ static int magicmouse_probe(struct hid_device *hdev,
> > goto err_free;
> > }
> >
> > - ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
> > + /* we are handling the input ourselves */
> > + ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW | HID_CONNECT_HIDDEV);
> > if (ret) {
> > dev_err(&hdev->dev, "magicmouse hw start failed\n");
> > goto err_free;
> > }
> >
> > - /* we are handling the input ourselves */
> > - hidinput_disconnect(hdev);
> > -
> > report = hid_register_report(hdev, HID_INPUT_REPORT, TOUCH_REPORT_ID);
> > if (!report) {
> > dev_err(&hdev->dev, "unable to register touch report\n");
>
> This effectively reverts commit 23d021167e. Has the HID core changed so
> that this won't cause problems when CONFIG_HIDRAW is disabled?
To answer my own question, it has not changed: If CONFIG_HIDRAW is
turned off, the device will not get attached with this change, so the
driver does not get any input to process. Turning CONFIG_HIDRAW on
restores the expected functionality.
Maybe hidinput_disconnect() should be modified instead, to clear the
fields that were causing null pointer dereferences?
Michael
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