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)]

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!