Re: [PATCH v2] i2c: acpi: Add DELL0A86 to i2c_acpi_force_100khz_device_ids

[Mika Westerberg]

+Andy

On Sun, Aug 23, 2026 at 08:33:10PM +0800, xiaoyueyoqwq wrote:
> The ELAN 04F3:3185 touchpad exposed as DELL0A86 on the Dell Inspiron
> 13 5310 intermittently exhibits excessive smoothing when the I2C bus
> runs at 400 kHz. During an affected period pointer movement becomes
> severely sluggish and sticky for tens of seconds.
> 
> The ACPI firmware configures the touchpad bus for 400 kHz. Add DELL0A86
> to i2c_acpi_force_100khz_device_ids so that the bus runs at 100 kHz, as
> is already done for other touchpads exhibiting the same excessive
> smoothing problem.
> 
> With the quirk applied, the kernel reports that the firmware requested
> 400 kHz and that the bus is forced to 100 kHz. The problem did not recur
> during extended heavy use, including an S4 hibernate/resume cycle.
> 
> Assisted-by: Codex:ChatGPT-5.6-Sol
> Assisted-by: OpenCode:Ox Alpha (x-preview-f-free)
> Signed-off-by: xiaoyueyoqwq <xiaoyueyoqwq@xxxxxxxxx>

You should use your full name here.

Anyway looks good to me.

Acked-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>

> ---
> Changes in v2:
> - Resend as non-flowed plain text; Thunderbird mangled whitespace in v1.
> - No code changes.
> 
>  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 8f3bdd5..3af0e05 100644
> --- a/drivers/i2c/i2c-core-acpi.c
> +++ b/drivers/i2c/i2c-core-acpi.c
> @@ -371,6 +371,7 @@ static const struct acpi_device_id i2c_acpi_force_100khz_device_ids[] = {
>  	 * the device works without issues on Windows at what is expected to be
>  	 * a 400KHz frequency. The root cause of the issue is not known.
>  	 */
> +	{ "DELL0A86", 0 },
>  	{ "DLL0945", 0 },
>  	{ "ELAN0678", 0 },
>  	{ "ELAN06FA", 0 },
> -- 
> 2.53.0