One of the main issues that drive me away from any libinput-based session towards xf86-driver-synaptics is the way two-finger scrolling is triggered - or, actually, sometimes not triggered - with libinput (with either xf86-driver-libinput, libinput debug tools or various Wayland compositors). The situation: The pointer is already moving with one finger and the second finger is placed on the touchpad. Expected result: pointer stops to move and content starts to scroll. Result got: pointer continues to move, no scrolling happens. xf86-driver-synaptics detects all the two-finger scrolls reliably and works as expected. With libinput, I always need to stop moving and only then can start scrolling, which is extremely annoying. dos@yoga:~$ pacman -Ss libinput extra/libinput 1.9.4-1 [installed] Laptop: Lenovo Yoga 900-13ISK # DMI: dmi:bvnLENOVO:bvrC6CN39WW:bd10/11/2016:svnLENOVO:pn80MK:pvrLenovoYOGA900-13ISK:rvnLENOVO:rnVIUU4:rvrSDK0J40709WIN:cvnLENOVO:ct10:cvrLenovoYOGA900-13ISK: # Input device name: "Synaptics TM3066-002" # Input device ID: bus 0x18 vendor 0x6cb product 0x77c6 version 0x100 # Size in mm: 87x57 The attached recording shows the example misinterpreted touchpad action. libinput-debug-events.txt shows the libinput's misinterpretation. However, when the recording is replayed with evemu-play, it's actually interpreted correctly (as seen in libinput-debug-events-replayed.txt).
Created attachment 136899 [details] evemu info
Created attachment 136900 [details] udev info
Created attachment 136901 [details] evemu recording Recording content: one finger placed on touchpad, moved to move the cursor, then second one placed and both moved together for a while in order to scroll.
Created attachment 136902 [details] libinput debug-events output, live, misinterpreted
Created attachment 136903 [details] libinput debug-events output, replayed, correct
Most likely a side-effect of bug 99703, this behaviour is intentional but should only be triggered above a certain movement speed. And it's the classic case of we have to pick a behaviour and thus get to choose which set of people to upset, sorry.
I understand that sometimes it's good to ignore such gesture due to it likely being a mistake, however, libinput is really, really stubborn with ignoring it even after I keep firmly moving two fingers together through the whole touchpad, which is hard to do by accident - I need to release the finger and touch again for it to start scrolling. I believe there should be some room to make this heuristic better without giving up on detecting accidents from bug 99703 :)
Yeah, I agree, we can be a bit more detailed here and check for motion distance/motion speed/something? Not sure what exactly though and I'm bottlenecking everywhere already, so I'll definitely will need help with that, sorry.
I find this two fingers scroll behavior annoying and unusable compare to the synaptics driver. I recently switched to Fedora 27 and reverted to Xorg/synaptics because of this..
not sure what your comment is supposed to achieve. it's not like bugs magically fix themselves if you switch to another driver.
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