On Mon, 29 Jan 2024, Dmitry Torokhov wrote:
> > From: Jason Gerecke <killertofu@xxxxxxxxx>
> >
> > If a input device is opened before hid_hw_start is called, events may
> > not be received from the hardware. In the case of USB-backed devices,
> > for example, the hid_hw_start function is responsible for filling in
> > the URB which is submitted when the input device is opened. If a device
> > is opened prematurely, polling will never start because the device will
> > not have been in the correct state to send the URB.
> >
> > Because the wacom driver registers its input devices before calling
> > hid_hw_start, there is a window of time where a device can be opened
> > and end up in an inoperable state. Some ARM-based Chromebooks in particular
> > reliably trigger this bug.
> >
> > This commit splits the wacom_register_inputs function into two pieces.
> > One which is responsible for setting up the allocated inputs (and runs
> > prior to hid_hw_start so that devices are ready for any input events
> > they may end up receiving) and another which only registers the devices
> > (and runs after hid_hw_start to ensure devices can be immediately opened
> > without issue). Note that the functions to initialize the LEDs and remotes
> > are also moved after hid_hw_start to maintain their own dependency chains.
> >
> > Fixes: 7704ac937345 ("HID: wacom: implement generic HID handling for pen generic devices")
> > Cc: stable@xxxxxxxxxxxxxxx # v3.18+
> > Suggested-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> > Signed-off-by: Jason Gerecke <jason.gerecke@xxxxxxxxx>
>
> Tested-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Applied, thanks!
--
Jiri Kosina
SUSE Labs
