Fix TrackPoint / touchpad issue on ThinkPad X1 Carbon 5th (Linux 4.12)

len0073.patch

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index 16c3046..ca912ce 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -173,6 +173,7 @@ static const char * const smbus_pnp_ids[] = {
        "LEN0046", /* X250 */
        "LEN004a", /* W541 */
        "LEN200f", /* T450s */
+       "LEN0073", /* X1 Carbon 5 (Elantech) */
        NULL
 };
 
diff --git a/drivers/input/rmi4/rmi_smbus.c b/drivers/input/rmi4/rmi_smbus.c
index 225025a..2939a2f 100644
--- a/drivers/input/rmi4/rmi_smbus.c
+++ b/drivers/input/rmi4/rmi_smbus.c
@@ -322,7 +322,7 @@ static int rmi_smb_probe(struct i2c_client *client,
        rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Smbus version is %d",
                smbus_version);
 
-       if (smbus_version != 2) {
+       if (smbus_version != 2 && smbus_version != 3) {
                dev_err(&client->dev, "Unrecognized SMB version %d\n",
                                smbus_version);
                return -ENODEV;

.config

$ grep -E 'HID_RMI|RMI4_SMB' .config
CONFIG_RMI4_SMB=m
CONFIG_HID_RMI=m

result

$ dmesg | grep -E 'psmouse|rmi4' 
[    1.537742] psmouse serio1: synaptics: queried max coordinates: x [..5678], y [..4758]
[    1.572729] psmouse serio1: synaptics: queried min coordinates: x [1266..], y [1094..]
[    1.574280] psmouse serio1: synaptics: Trying to set up SMBus access
[    1.578731] psmouse serio1: synaptics: SMbus companion is not ready yet
[    1.645578] psmouse serio1: synaptics: Touchpad model: 1, fw: 8.2, id: 0x1e2a1, caps: 0xf003a3/0x940300/0x12e800/0x0, board id: 3288, fw id: 2538625
[    1.647134] psmouse serio1: synaptics: serio: Synaptics pass-through port at isa0060/serio1/input0
[    2.056868] psmouse serio2: Failed to reset mouse on synaptics-pt/serio0
[    7.696884] psmouse serio2: Failed to enable mouse on synaptics-pt/serio0
[    8.997307] psmouse serio1: synaptics: queried max coordinates: x [..5678], y [..4758]
[    9.032026] psmouse serio1: synaptics: queried min coordinates: x [1266..], y [1094..]
[    9.032037] psmouse serio1: synaptics: Trying to set up SMBus access
[    9.045519] rmi4_smbus 6-002c: registering SMbus-connected sensor
[    9.108224] rmi4_f01 rmi4-00.fn01: found RMI device, manufacturer: Synaptics, product: TM3288-003, fw id: 2538625
[    9.178951] input: Synaptics TM3288-003 as /devices/rmi4-00/input/input9
[   10.541603] input: PS/2 Generic Mouse as /devices/rmi4-00/rmi4-00.fn03/serio3/input/input18

$ xinput
⎡ Virtual core pointer                        id=2    [master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer                id=4    [slave  pointer  (2)]
⎜   ↳ Synaptics TM3288-003                      id=11   [slave  pointer  (2)]
⎜   ↳ PS/2 Generic Mouse                      	id=12   [slave  pointer  (2)]
⎣ Virtual core keyboard                       id=3    [master keyboard (2)]
    ↳ Virtual core XTEST keyboard                 id=5    [slave  keyboard (3)]
    ↳ Power Button                                id=6    [slave  keyboard (3)]
    ↳ Video Bus                                   id=7    [slave  keyboard (3)]
    ↳ Sleep Button                                id=8    [slave  keyboard (3)]
    ↳ AT Translated Set 2 keyboard                id=9    [slave  keyboard (3)]
    ↳ ThinkPad Extra Buttons                      id=10   [slave  keyboard (3)]

I've just confirmed that these changes, included in 4.12.10, conflict with this patch set.

The middle click on the trackpoint will not work if both the commit and the changes in this gist are applied.

This patch, soon to be merged from linux-input to linux-stable, seems to work around the problem mentioned above...
IMO not a good fix, but it works with the patches in this gist.
https://patchwork.kernel.org/patch/9944117/

https://patchwork.kernel.org/patch/9928843/

Seems someone has already submitted the patch.

Since 4.14 you can just add psmouse.synaptics_intertouch=1 in the boot parameters.

I can confirm the params make my trackpad work on 4.15.

I wonder why it works with those kernel params, even though the LEN0073 part is not merged in.

psmouse.synaptics_intertouch=1 helps with the trackpad on T460p!