Re: [PATCH 1/1] Force ELAN06FA touchpad I2C bus freq to 100KHz

Jarkko Nikula
2025-01-10T11:45:07Z

On 1/10/25 1:26 PM, Mika Westerberg wrote:
> Hi,
>
> On Fri, Jan 10, 2025 at 02:31:26AM -0600, R Ha wrote:
>> Hi,
>>
>> Sounds like a good idea. I'm a little worried I'm missing something,
>> so I think being able to check my earlier answers will help as well.
>> I'm sending the entire output as attachments, but let me know if it's
>> better to upload them somewhere and paste the link instead. Some of
>> the ssdt* files are missing, but they're empty files so Gmail won't
>> let me attach them.
>
> Thanks for sharing! Okay checked now dsdt.dsl (the other files are not
> relevant here) and what I can tell the device is supposed to be run at 400
> kHz. I suspect this is what Windows is doing as well, there is nothing that
> indicates otherwise.
>
> And since this is a standard I2C HID device it should just work (as it does
> not require any vendor specific driver even in Windows).
>
> Only thing I can think of that affects this is the LCNT/HCNT and SDA hold
> values of the I2C designware controller (and maybe the input clock) but
> there is nothing in the ACPI tables that set these so it could be that the
> Windows driver uses different values for those and that explains why it
> works better there.
>
> @Jarkko, do you have any input here? If we cannot figure a better way then
> I don't see other option than to add this quirk.

Unfortunately I don't have idea.