HID: wacom: Defer calculation of resolution until resolution_code is known

The Wacom driver maps the HID_DG_TWIST usage to ABS_Z (rather than ABS_RZ)
for historic reasons. When the code to support twist was introduced in
commit 50066a042da5 ("HID: wacom: generic: Add support for height, tilt,
and twist usages"), we were careful to write it in such a way that it had
HID calculate the resolution of the twist axis assuming ABS_RZ instead
(so that we would get correct angular behavior). This was broken with
the introduction of commit 08a46b4190d3 ("HID: wacom: Set a default
resolution for older tablets"), which moved the resolution calculation
to occur *before* the adjustment from ABS_Z to ABS_RZ occurred.

This commit moves the calculation of resolution after the point that
we are finished setting things up for its proper use.

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Fixes: 08a46b4190d3 ("HID: wacom: Set a default resolution for older tablets")
Cc: stable@vger.kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.com>

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index 1f4564982b958448cdfbe15d7c88bb3693891733..2541fa2e0fa3b15aff4f393d314f740cdb597ea4 100644 (file)
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -1878,12 +1878,14 @@ static void wacom_map_usage(struct input_dev *input, struct hid_usage *usage,
        int fmax = field->logical_maximum;
        unsigned int equivalent_usage = wacom_equivalent_usage(usage->hid);
        int resolution_code = code;
-       int resolution = hidinput_calc_abs_res(field, resolution_code);
+       int resolution;
 
        if (equivalent_usage == HID_DG_TWIST) {
                resolution_code = ABS_RZ;
        }
 
+       resolution = hidinput_calc_abs_res(field, resolution_code);
+
        if (equivalent_usage == HID_GD_X) {
                fmin += features->offset_left;
                fmax -= features->offset_right;