HID: wacom: Call 'wacom_query_tablet_data' only after 'hid_hw_start' (86e88f0e) · Commits · 戴 / test

When connecting the Cintiq Companion 2 as an external tablet (i.e., using it in "hybrid" mode) it has been seen to cause the kernel of the machine it is connected to to Oops. The cause has been traced to us attempting to switch the tablet's mode prior to actually starting HID device (resulting in the eventual dereference of the uninitialized control URB). Commit moved the mode switch from occuring post-start to occurring pre-start. The change was not seen to cause issues largely due to the fact that most devices mode switch with 'hid_hw_raw_request' (which is safe to call prior to start) rather than 'hid_hw_request'. Moving the call back to its original location resolves the issue, but causes some touch-only Bamboo tablets (e.g. 056a:00d0) to stop working. The affected tablets require us to perform a mode switch on their vestigial pen interface prior ignoring with -ENODEV, meaning that the code which is responsible for doing the ignoring has to move as well. Signed-off-by:

Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by:

Ping Cheng <pingc@wacom.com> Signed-off-by:

Jiri Kosina <jkosina@suse.cz>

drivers/hid/wacom_sys.c

+18 −18

Original line number	Diff line number	Diff line
		@@ -1778,24 +1778,6 @@ static int wacom_probe(struct hid_device *hdev,
		features->device_type \|= WACOM_DEVICETYPE_PEN;
		}

		/* Note that if query fails it is not a hard failure */
		wacom_query_tablet_data(hdev, features);

		/* touch only Bamboo doesn't support pen */
		if ((features->type == BAMBOO_TOUCH) &&
		(features->device_type & WACOM_DEVICETYPE_PEN)) {
		error = -ENODEV;
		goto fail_shared_data;
		}

		/* pen only Bamboo neither support touch nor pad */
		if ((features->type == BAMBOO_PEN) &&
		((features->device_type & WACOM_DEVICETYPE_TOUCH) \|\|
		(features->device_type & WACOM_DEVICETYPE_PAD))) {
		error = -ENODEV;
		goto fail_shared_data;
		}

		wacom_calculate_res(features);

		wacom_update_name(wacom);
		@@ -1833,6 +1815,24 @@ static int wacom_probe(struct hid_device *hdev,
		goto fail_hw_start;
		}

		/* Note that if query fails it is not a hard failure */
		wacom_query_tablet_data(hdev, features);

		/* touch only Bamboo doesn't support pen */
		if ((features->type == BAMBOO_TOUCH) &&
		(features->device_type & WACOM_DEVICETYPE_PEN)) {
		error = -ENODEV;
		goto fail_hw_start;
		}

		/* pen only Bamboo neither support touch nor pad */
		if ((features->type == BAMBOO_PEN) &&
		((features->device_type & WACOM_DEVICETYPE_TOUCH) \|\|
		(features->device_type & WACOM_DEVICETYPE_PAD))) {
		error = -ENODEV;
		goto fail_hw_start;
		}

		if (features->device_type & WACOM_DEVICETYPE_WL_MONITOR)
		error = hid_hw_open(hdev);

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