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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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i2c: acpi: Add ELAN0678 to i2c_acpi_force_100khz_device_ids

The ELAN0678 touchpad (04F3:3195) found in the Lenovo ThinkPad X13
exhibits excessive smoothing when the I2C bus runs at 400KHz, making
the touchpad feel sluggish when plugged into AC power. This is the
same issue previously fixed for ELAN06FA.

The device's ACPI table (Lenovo TP-R22) specifies 0x00061A80 (400KHz)
for the I2cSerialBusV2 descriptor. Forcing the bus to 100KHz eliminates
the sluggish behavior.

Signed-off-by: Niels Franke <nielsfranke@gmail.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
[wsa: kept the sorting]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

authored by

Niels Franke and committed by
Wolfram Sang 9998e388 c5f25f58

+1
+1
drivers/i2c/i2c-core-acpi.c
··· 371 371 * a 400KHz frequency. The root cause of the issue is not known. 372 372 */ 373 373 { "DLL0945", 0 }, 374 + { "ELAN0678", 0 }, 374 375 { "ELAN06FA", 0 }, 375 376 {} 376 377 };