HID: wacom: fix an Oops caused by wacom_wac_finger_count_touches

We assumed all touch interfaces report touch data. But, Bamboo
and Intuos non-touch devices report express keys on touch
interface. We need to check touch_max before counting touches.

Reported-by: Tasos Sahanidis <tasos@tasossah.com>
Signed-off-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Ping Cheng 2015-05-19 17:42:02 -07:00 committed by Jiri Kosina
parent 849eca7b9d
commit 26ba61f871

View File

@ -1072,6 +1072,9 @@ static int wacom_wac_finger_count_touches(struct wacom_wac *wacom)
int count = 0;
int i;
if (!touch_max)
return 0;
/* non-HID_GENERIC single touch input doesn't call this routine */
if ((touch_max == 1) && (wacom->features.type == HID_GENERIC))
return wacom->hid_data.tipswitch &&