HID: wacom: Expect 'touch_max' touches if HID_DG_CONTACTCOUNT not present
authorJason Gerecke <killertofu@gmail.com>
Wed, 7 Oct 2015 23:54:22 +0000 (16:54 -0700)
committerJiri Kosina <jkosina@suse.cz>
Wed, 21 Oct 2015 11:13:12 +0000 (13:13 +0200)
commitdf7079380554e6e8e13a0812c7e6c72f669aba5c
treec9f89bc0571cb94db2268da6836ccb11278f7ca8
parent499522c8c015de995aabce3d0f0bf4b9b17f44c3
HID: wacom: Expect 'touch_max' touches if HID_DG_CONTACTCOUNT not present

When introduced in commit 1b5d514, the check 'if (hid_data->cc_index >= 0)'
in 'wacom_wac_finger_pre_report' was intended to switch where the driver
got the expected number of contacts from: HID_DG_CONTACTCOUNT if the usage
was present, or 'touch_max' otherwise. Unfortunately, an oversight worthy
of a brown paper bag (specifically, that 'cc_index' could never be negative)
meant that the latter 'else' clause would never be entered.

The patch prior to this one introduced a way for 'cc_index' to be negative,
but only if HID_DG_CONTACTCOUNT is present in some report _other_ than the
one being processed. To ensure the 'else' clause is also entered for devices
which don't have HID_DG_CONTACTCOUNT on _any_ report, we add the additional
constraint that 'cc_report' be non-zero (which is true only if the usage is
present in some report).

Cc: stable@vger.kernel.org
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
drivers/hid/wacom_wac.c