[1/1] Input: trackpoint - force 3 buttons if 0 button is reported
diff mbox series

Message ID 20180129143224.12879-2-aaron.ma@canonical.com
State New
Headers show
  • TrackPoint: enable middle button on compatible sticks
Related show

Commit Message

Aaron Ma Jan. 29, 2018, 2:32 p.m. UTC
BugLink: https://bugs.launchpad.net/bugs/1746002

Lenovo introduced trackpoint compatible sticks with minimum PS/2 commands.
They supposed to reply with 0x02, 0x03, or 0x04 in response to the
"Read Extended ID" command, so we would know not to try certain extended
commands. Unfortunately even some trackpoints reporting the original IBM
version (0x01 firmware 0x0e) now respond with incorrect data to the "Get
Extended Buttons" command:

 thinkpad_acpi: ThinkPad BIOS R0DET87W (1.87 ), EC unknown
 thinkpad_acpi: Lenovo ThinkPad E470, model 20H1004SGE

 psmouse serio2: trackpoint: IBM TrackPoint firmware: 0x0e, buttons: 0/0

Since there are no trackpoints without buttons, let's assume the trackpoint
has 3 buttons when we get 0 response to the extended buttons query.

Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=196253
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
(cherry picked from commit f5d07b9e98022d50720e38aa936fc11c67868ece)
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
 drivers/input/mouse/trackpoint.c | 3 +++
 1 file changed, 3 insertions(+)

diff mbox series

diff --git a/drivers/input/mouse/trackpoint.c b/drivers/input/mouse/trackpoint.c
index 0871010f18d5..92a8898682a6 100644
--- a/drivers/input/mouse/trackpoint.c
+++ b/drivers/input/mouse/trackpoint.c
@@ -383,6 +383,9 @@  int trackpoint_detect(struct psmouse *psmouse, bool set_properties)
 	if (trackpoint_read(ps2dev, TP_EXT_BTN, &button_info)) {
 		psmouse_warn(psmouse, "failed to get extended button data, assuming 3 buttons\n");
 		button_info = 0x33;
+	} else if (!button_info) {
+		psmouse_warn(psmouse, "got 0 in extended button data, assuming 3 buttons\n");
+		button_info = 0x33;
 	psmouse->private = kzalloc(sizeof(struct trackpoint_data), GFP_KERNEL);