a9ce7856ca
Commit 345857b ("HID: wacom: generic: Add support for sensor offsets") included
a change to the operation and location of the call to 'wacom_add_shared_data'
in 'wacom_parse_and_register'. The modifications included moving it higher up
so that it would occur before the call to 'wacom_retrieve_hid_descriptor'. This
was done to prevent a crash that would have occured when the report containing
tablet offsets was fed into the driver with 'wacom_hid_report_raw_event'
(specifically: the various 'wacom_wac_*_report' functions were written with the
assumption that they would only be called once tablet setup had completed;
'wacom_wac_pen_report' in particular dereferences 'shared' which wasn't yet
allocated).
Moving the call to 'wacom_add_shared_data' effectively prevented the crash but
also broke the sibiling detection code which assumes that the HID descriptor
has been read and the various device_type flags set.
To fix this situation, we restore the original 'wacom_add_shared_data'
operation and location and instead implement an alternative change that can
also prevent the crash. Specifically, we notice that the report functions
mentioned above expect to be called only for input reports. By adding a check,
we can prevent feature reports (such as the offset report) from
causing trouble.
Fixes: 345857bb49 ("HID: wacom: generic: Add support for sensor offsets")
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Tested-by: Ping Cheng <pingc@wacom.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.