Downgrading from Win 8 and making I2C touchpad work with W 7

[kyk]

I have downgraded Lenovo Yoga 3 Pro-1370 to Windows 7-64 and its touchpad (Synaptics) is not detected by Windows at all (and not shown in Device Manager). As far as I understand, the touchpad is connected via I2C interface (not USB or PS2). I2C is handled by Windows 8 at a systemic level and very differently from Windows 7.

Lenovo does not support Windows 7 on Yoga 3 and does not provide Windows 7 drivers.

I tried different Win7 Synaptics drivers from other Lenovo models as well as generic drivers from Synaptics. No success.

What is the likelihood of making the touchpad to work with Windows 7? Will OEM drivers from other manufactures possibly work?

For Windows 8, the Yoga 3 chipset includes ‘Intel Serial I/O Driver’ which (I guess) takes care of I2C.

In Windows 8 Device Manager, there are 3 devices related to the touchpad:

Touchpad itself

Code: Select all

HID\VEN_SYNA&DEV_2B22&Col01
HID\SYNA2B22&Col01
HID\*SYNA2B22&Col01
HID_DEVICE_SYSTEM_MOUSE
HID_DEVICE_UP:0001_U:0002
HID_DEVICE
Driver: Synaptics

Intel(R) Serial IO I2C Host Controller - 9CE1

Location: on PCI Express Root Complex
Driver: 'iaLPSS_I2C.sys' (Intel)
ACPI\VEN_INT&DEV_3432&REV_0003
ACPI\VEN_INT&DEV_3432
ACPI\INT3432
*INT3432
Enumerator: ACPI
oem7.inf

I2C HID Device (on Intel Serial IO I2C Host Controller - 9CE1)

ACPI\VEN_SYNA&DEV_2B22
ACPI\SYNA2B22
*SYNA2B22
Compatible Ids: ACPI\PNP0C50
HID\SYNA2B22&Col01\5&f4a3470&0&0000
HID\SYNA2B22&Col02\5&f4a3470&0&0001
Parent: ACPI\INT3432\3&11583659&0
Driver: Microsoft
Enumerator: ACPI
hidi2c.inf

Lenovo Yoga 3 Pro-1370, Intel Core M (CPU: 5Y70)

Windows 8 introduces support for HID over I2C