Re: [PATCH] HID: quirks: Add Apple Magic Trackpad 2 to hid_have_special_driver list

[Benjamin Tissoires <benjamin.tissoires@redhat.com>]

Hi Felix,

On Wed, Dec 2, 2020 at 5:31 AM Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
>
> On Thu, Nov 19, 2020 at 12:31 AM Felix Hädicke <felixhaedicke@web.de> wrote:
> >
> > The Apple Magic Trackpad 2 is handled by the magicmouse driver. And
> > there were severe stability issues when both drivers (hid-generic and
> > hid-magicmouse) were loaded for this device.
> >
> > Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=210241

As mentioned in the bug, this hardly looks like the correct solution.

The magicmouse is one of the 2 only drivers that calls
`hid_register_report` and then overwrites the size of the report
manually. I can not figure out immediately if this is wrong, and how
that would impact a free in usbhid, but this is highly suspicious to
me.

Cheers,
Benjamin

>
> +Jiri Kosina +Benjamin Tissoires for visibility.
>
> >
> > Signed-off-by: Felix Hädicke <felixhaedicke@web.de>
> > ---
> >  drivers/hid/hid-quirks.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c
> > index 7a2be0205dfd..0a589d956e5c 100644
> > --- a/drivers/hid/hid-quirks.c
> > +++ b/drivers/hid/hid-quirks.c
> > @@ -473,6 +473,8 @@ static const struct hid_device_id hid_have_special_driver[] = {
> >  #if IS_ENABLED(CONFIG_HID_MAGICMOUSE)
> >         { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGICMOUSE) },
> >         { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGICTRACKPAD) },
> > +       { HID_BLUETOOTH_DEVICE(BT_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGICTRACKPAD2) },
> > +       { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGICTRACKPAD2) },
> >  #endif
> >  #if IS_ENABLED(CONFIG_HID_MAYFLASH)
> >         { HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, USB_DEVICE_ID_DRAGONRISE_PS3) },
> > --
> > 2.29.2
> >
>
> Thanks.
>
> --
> Dmitry
>