Hey
On Wed, Jan 10, 2018 at 4:03 PM, Andy Shevchenko
<andy.shevchenko@xxxxxxxxx> wrote:
> On Tue, Jan 9, 2018 at 10:24 PM, Matthew Thode <mthode@xxxxxxxxxx> wrote:
>> On 18-01-09 22:16:10, Andy Shevchenko wrote:
>>> On Tue, Jan 9, 2018 at 3:19 PM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote:
>
>> I've been able to trigger it 'at will' on the X1C5. If I hover my hand
>> just below the arrow keys I'll get the first signal, after I take it
>> away I get the second one. There seems to be a delay in when I put (or
>> take away) my hand to prevent spamming the logs even more. It could be
>> to sense lid close, but there's already another sensors for that I
>> thought. The only remaining thing I can guess it that it's to detect
>> your hands to turn on the keyboard backlight or something.
>>
>> I don't think it's related at all to the fingerprint sensor as I hover
>> my hand to the right of it.
>
> Just realized that it might be an ambient sensor. Your hand makes
> light goes differently to the sensor -> hardware sends an event.
>
> Whatever guys, feel free to submit a patch when you will be sure what
> is the source of the event.
>
> It also makes sense to discuss somewhere near to thinkwiki.org I suppose.
Indeed. I can reliably trigger it by moving my hand on top of the
arrow-keys. 0x60b0 is signaled when hovered. It has a latency of
roughly 1s. Once I remove my hand, 0x60b1 is signalled, with a latency
of roughly 3s. Overall, the sensor is quite unreliable when I actually
use the laptop. Sometimes to a degree that it does not react to
anything at all. It might really be some ambient light sensor, which
then gets confused by some unexpected lighting.
Whatever it is, I think this is really meant as "palm-detection" so
input drivers can disable trackpads, etc.
I'd be fine with the patch Matthew proposed (makes the sensor a no-op):
https://www.snip2code.com/Snippet/3291964/0001-Add-Thinkpad-palm-detection-acpi-co/
Andy, is there any reason not to merge it? Do you want this key to be
exposed in some way? If the patch is ok, I can test it locally and
resend with tested-by.
Thanks
David
