[Wayland-bugs] [Bug 103813] Synaptics Touchpad is not precise. Very hard to hit small buttons. Instead of moving fluently it seems to skip a few pixels.

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=103813

Peter Hutterer <peter.hutterer at who-t.net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEEDINFO                    |NEW

--- Comment #8 from Peter Hutterer <peter.hutterer at who-t.net> ---
the stair pattern should be gone with the hysteresis gone?

If one prints the per-slot deltas the problem is visible:

 0.148118:              |  *********** | 
 0.176980:              |  *********** | 
 0.207288:              |  *********** | 
 0.226218:              |  *********** | 
 0.236147:              |  *********** | 
 0.246356: ↑↗   31/ -43 |  *********** | 
 0.314911: →↘   31/   7 |  *********** | 
 0.325129: →↘   31/   4 |  *********** | 
 0.335191: →↘   31/   1 |  *********** | 
 0.364298: →↗   31/  -6 |  *********** | 
 0.374541: →↘   31/   4 |  *********** | 
 0.383795: →↘   31/   1 |  *********** | 
 0.393685: →↘    7/   1 |  *********** | 
 0.403613: →↘    5/   1 |  *********** | 
 0.413709: →↘    1/   1 |  *********** | 
 0.423796: ↓↘    1/   4 |  *********** | 
 0.432893: →↘    1/   1 |  *********** | 
 0.443063: →↘    1/   1 |  *********** | 

so no movement, then several movemnts with 31 units (42 units == 1mm), then
smaller movements. This repeats often:

 2.167606: →↘    1/   1 |  *********** | 
 2.177573: →↘    1/   1 |  *********** | 
 2.187647: →↘    4/   1 |  *********** | 
 2.196651: ↓↘    1/  18 |  *********** | 
 2.206751: →↘   20/  18 |  *********** | 
 2.226926: ↓↘    1/  18 |  *********** | 
 2.236070: ↓↘    1/  18 |  *********** | 
 2.246686: ↓↘    1/  18 |  *********** | 
 2.255925: ↓↘    1/  18 |  *********** | 
 2.265937: ↓↘    1/  18 |  *********** | 
 2.275980: ↓↘    1/  18 |  *********** | 
 2.285035: ↑↗    1/  -7 |  *********** | 


That 20 in there would give you a jump. In other words, the data coming out of
the device is bad and we need some code to detect and paper over these jumps.
Not sure how to do this yet, suggestions appreciated

Tool used:
https://github.com/whot/input-data-analysis/tree/master/per-slot-deltas

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/wayland-bugs/attachments/20171122/bc02fbce/attachment.html>