On Tue, May 21, 2019 at 7:09 AM Dmitry Torokhov
[off-list ref] wrote:

Hi Aaron,

On Sun, May 19, 2019 at 03:27:11PM +0800, Aaron Ma wrote:

quoted

Lenovo ThinkPad X240 does not have the top software button.
When this wrong ID in top button list, smbus mode will fail to probe,
so keep it working at PS2 mode.

Cc: stable@vger.kernel.org
Signed-off-by: Aaron Ma <redacted>
---
 drivers/input/mouse/synaptics.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index b6da0c1267e3..6ae7bc92476b 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c

@@ -140,7 +140,6 @@ static const char * const topbuttonpad_pnp_ids[] = {
      "LEN002E",
      "LEN0033", /* Helix */
      "LEN0034", /* T431s, L440, L540, T540, W540, X1 Carbon 2nd */
-     "LEN0035", /* X240 */

According to the history this came from Synaptics through Hans, so I'd
like to make sure there are no several X240 versions floating around...

A quick google image search showed that the X240 had 2 versions: one
with the top software buttons, one without.

And this definitively rings a bell. I am sure we asked Lenovo and
Synaptics to change the PnPID when they would do such a change, but
they "forgot" during the *40 series refresh.
We have code in place to fix the reported ranges of the coordinates,
and we had to check against the board id (see min_max_pnpid_table[] in
synaptics.c).
Unfortunately, X240 (LEN0035) is not part of this table, so I don't
know which refresh of the board ID has implemented the non top
software buttons.

Cheers,
Benjamin

quoted

      "LEN0036", /* T440 */
      "LEN0037", /* X1 Carbon 2nd */
      "LEN0038",
--
2.17.1

Thanks.

--
Dmitry