[PATCH 3.16 225/254] Input: trackpoint - assume 3 buttons when buttons detection fails

[Ben Hutchings]

3.16.55-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Oscar Campos <oscar.campos@xxxxxxxxxxxxxx>

commit 293b915fd9bebf33cdc906516fb28d54649a25ac upstream.

Trackpoint buttons detection fails on ThinkPad 570 and 470 series,
this makes the middle button of the trackpoint to not being recogized.
As I don't believe there is any trackpoint with less than 3 buttons this
patch just assumes three buttons when the extended button information
read fails.

Signed-off-by: Oscar Campos <oscar.campos@xxxxxxxxxxxxxx>
Acked-by: Peter Hutterer <peter.hutterer@xxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/input/mouse/trackpoint.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/input/mouse/trackpoint.c
+++ b/drivers/input/mouse/trackpoint.c
@@ -377,8 +377,8 @@ int trackpoint_detect(struct psmouse *ps
 		return 0;
 
 	if (trackpoint_read(&psmouse->ps2dev, TP_EXT_BTN, &button_info)) {
-		psmouse_warn(psmouse, "failed to get extended button data\n");
-		button_info = 0;
+		psmouse_warn(psmouse, "failed to get extended button data, assuming 3 buttons\n");
+		button_info = 0x33;
 	}
 
 	psmouse->private = kzalloc(sizeof(struct trackpoint_data), GFP_KERNEL);