[RMI4/SMBus Test Report] Lenovo ThinkPad E495 touchpad intertouch attempt (LEN205d PNP0f13)

Hi Linux Input Team,

I am writing because dmesg output on this Debian Trixie 13.6 suggested 
as much. This mail reports the result of testing 
`psmouse.synaptics_intertouch=1` on a Lenovo ThinkPad E495, as suggested 
by the psmouse driver in dmesg.

Hardware Details:
- Laptop: Lenovo ThinkPad E495 (20NE)
- Touchpad PNP ID: LEN205d (PNP0f13)
- OS: Debian 13 (Trixie)
- Kernel: 6.12.100+deb13-amd64 (very vanilla)

Pre-test setup check:
Neither `i2c-hid` nor `hid-rmi` were driving the device. The touchpad 
was bound to the legacy PS/2 bus 
(`/devices/platform/i8042/serio1/input/input7`). `lsmod` showed no 
active module usages for `i2c_hid` or `hid_rmi`.

Test Result with `psmouse.synaptics_intertouch=1`:
When booting with `psmouse.synaptics_intertouch=1`, intertouch 
initialization fails due to timing/readiness issues with the SMBus 
companion, causing psmouse to fall back to standard PS/2 mode.

Relevant dmesg snippet:

[    0.018317] Kernel command line: 
BOOT_IMAGE=/boot/vmlinuz-6.12.100+deb13-amd64 
root=UUID=d8389723-dbf0-4502-ac1a-4d9c9ac601c0 ro quiet splash 
psmouse.synaptics_intertouch=1
...
[    2.492227] psmouse serio1: synaptics: queried max coordinates: x 
[..5678], y [..4694]
[    2.538765] psmouse serio1: synaptics: queried min coordinates: x 
[1266..], y [1162..]
[    2.538777] psmouse serio1: synaptics: Trying to set up SMBus access
[    2.543173] psmouse serio1: synaptics: SMbus companion is not ready yet
[    2.645656] psmouse serio1: synaptics: Touchpad model: 1, fw: 10.32, 
id: 0x1e2a1, caps: 0xf014a3/0x940300/0x12e800/0x500000, board id: 3471, 
fw id: 3972349
[    2.645683] psmouse serio1: synaptics: serio: Synaptics pass-through 
port at isa0060/serio1/input0
[    2.709409] input: SynPS/2 Synaptics TouchPad as 
/devices/platform/i8042/serio1/input/input7
[    3.370088] psmouse serio2: trackpoint: Elan TrackPoint firmware: 
0x11, buttons: 3/3
[    3.672181] input: TPPS/2 Elan TrackPoint as 
/devices/platform/i8042/serio1/serio2/input/input8

The touchpad continues to function normally (multitouch gesture) via 
PS/2 fallback, but as I understand from this SMBus access could not be 
established.

Please let me know if you need further logs or would like me to test a 
patch or additional kernel parameters.

Best regards,
Carsten

(Gentoo linux user usually)