[PATCH libinput v4 0/2] Fix Lenovo X230 series touchpad

Giulio Camuffo giuliocamuffo at gmail.com
Wed Apr 22 08:57:37 PDT 2015


Hi,

sorry to bikeshed but imho the v1, while maybe too slow, was better
than this one. Imho the acceleration curve is too abrupt, i find that
sometimes i'm trying to move the pointer some tens of pixels away so i
move the finger slowly, only it's too slow so i accelerate a bit and i
end up swooping away to the side of the screen.
I vote v1 rather than this, however since it's a subjective issue and
i can't promise to put my time in this i won't get offended if this
gets merged ;).

Cheers,
Giulio


2015-04-20 21:29 GMT+03:00 Benjamin Tissoires <benjamin.tissoires at gmail.com>:
> Hi,
>
> This is a new attempt to fix the X230 series.
>
> This time, I tried to put some more scientific effort, and used gnuplot
> to try to understand what was happening and how we could catch the same
> acceleration at high speed than regular touchpads.
>
> The results are synthetized in this png:
> http://people.freedesktop.org/~tissoire/x230.png
>
> The red-ish lines are the ones plotted from the regular touchpad acceleration
> profile for different speed settings (-1.0, 0.0, 1.0).
>
> The black one is the one I submitted in the v1 of this series.
> You can see that the max speed is caught when the input speed is 5, which is
> not the common use case.
>
> So I tried to implement what I wanted to do the first time:
> - at low speed, slow down the cursor
> - at high speed (> 2), catch up with the other touchpads
> - find something acceptable in the middle
>
> Not having to use the generic linear pointer acceleration made things much
> easier to tune, and I ended up with the code in patch 1/2.
>
> If other users of the X230 find this acceptable, I propose that we merge this
> and then we try to tune it later.
>
> My believe is that unless we properly filter the incoming events, we won't be
> able to have a smooth solution. Nevertheless, I feel that these settings
> should be OK.
>
> Cheers,
> Benjamin
>
> Benjamin Tissoires (2):
>   evdev: use a different filter for low resolution touchpad on the
>     Lenovo X230
>   udev: add a custom udev rule for X230 touchpads
>
>  doc/device-configuration-via-udev.dox |    9 +++++++
>  src/evdev-mt-touchpad.c               |   14 +++++++++--
>  src/evdev.c                           |   23 +++++++++++++++++++
>  src/evdev.h                           |    7 +++++
>  src/filter.c                          |   40 +++++++++++++++++++++++++++++++++
>  src/filter.h                          |    5 ++++
>  udev/90-libinput-model-quirks.rules   |   14 +++++++++++
>  udev/Makefile.am                      |    4 ++-
>  8 files changed, 112 insertions(+), 4 deletions(-)
>  create mode 100644 udev/90-libinput-model-quirks.rules
>
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