[PATCH v3 0/4] Fix Lenovo X230 series touchpad

[Benjamin Tissoires]

Hi Vasily,

On Fri, Apr 17, 2015 at 2:47 AM, Vasily Khoruzhick <anarsoul at gmail.com> wrote:
> Hi Benjamin,
>
> On Thu, Apr 16, 2015 at 9:41 PM, Benjamin Tissoires
> <benjamin.tissoires at gmail.com> wrote:
>> So here is a v2 (well v3 to keep things incrementing) of the x230 touchpad
>> series.
>>
>> The touchpad seems almost as fast as any other by multiplying again the
>> incline parameter by TP_MAGIC_LOW_RES_FACTOR. I am sure there is an explanation
>> here, but I won't give it.
>
> New settings are unusable on my x230. Difference between slow and fast
> movement is too high, it's hard to position cursor on some small
> button, etc.

So maybe the X230t has a slightly different touchpad. I don't recall
having any difficulties with the new patch series.
I think I'll just revert to the v1 settings. But if you can try to
tune the parameters, that would be better than me having to borrow the
x230t for part of a day, do quick tests and decide that it feels
normal.

>
>> I also did not felt now that the scroll was too laggy. If you scroll slow, then
>> yes you have a 2 lines scroll for the whole height of the touchpad. But at
>> normal speed, I found it OK.
>
> Scroll _IS_ laggy. Just compare it with normal touchpad. Moving finger
> through half of touchpad height to scroll for a single line is not OK,
> and I can't get it scrolling for exactly one line with faster
> movement.

Again, we might have a different FW settings on the X230 and the
X230t. I know that we can not have the exact same feeling that what is
available on the other (correct) touchpads. On these, the sensors
forward a X/Y delta when you move your finger for a few millimeters,
while the others continuously report events. So we have to take the
less worse solution.

And in this case, you and all the other regular users of these
touchpad should choose the best settings. It's a matter of putting a
random factor in touchpad_lenovo_x230_accel_profile(), rebuilding,
installing and killing X or wayland (you can also directly use
tools/event-gui without having to install/and kill your session):
- max_accel has no (or little) impact from what I could say, we do not
seem to hit this value
- threshold will decide when to start accelerating, the higher you
set, the later acceleration hits
- incline will affect the speed factor of the cursor (the higher, the faster)

BTW, we never said that the values we are going to put in libinput now
will be the final ones. There is room to improvement. We can even
change the whole acceleration function if needed. The goal is to be
able to tune this touchpad to be usable, and then we can just forget
about it because no one else will change it inadvertently.

Cheers,
Benjamin