[PATCH] i2c: acpi: Force ELAN1300 touchpads to 100 kHz

[Abhijeeth Babu]

The ELAN1300 touchpad with HID ID 04F3:3104 on the ASUS VivoBook
X513UA_KM513UA exhibits severe pointer jumps and erratic movement when
the I2C bus operates at 400 kHz.

The system DSDT describes the touchpad using an I2cSerialBusV2 resource
with a speed of 0x00061A80, corresponding to 400 kHz, on the
AMDI0010:03 controller.

At this speed, libinput repeatedly reports:

kernel bug: Touch jump detected and discarded

Add ELAN1300 to i2c_acpi_force_100khz_device_ids so that it operates at
100 kHz.

Before the change, nine touch-jump events were recorded, with additional
messages suppressed by libinput's rate limiter. With the bus forced to
100 kHz, no touch-jump events have been observed and the touchpad operates
normally.

The affected system uses BIOS X513UA.319 dated 2023-05-09.

Signed-off-by: Abhijeeth Babu <babu.jeeth@xxxxxxxxx>
---
 drivers/i2c/i2c-core-acpi.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index e5fddacae..763743d5d 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -376,6 +376,7 @@ static const struct acpi_device_id i2c_acpi_force_100khz_device_ids[] = {
 	{ "DLL0945", 0 },
 	{ "ELAN0678", 0 },
 	{ "ELAN06FA", 0 },
+	{ "ELAN1300", 0 },
 	{}
 };
 
-- 
2.54.0