you're still using the synaptics driver which doesn't do gestures. libinput does, but it merely passes on the recognised gestures to the next layer. in the case of Wayland, that's the compositor and some compositors support touchpad gestures. In the case of X, no touchpad gestures are available, so this won't work directly in X without some other tool.

touchegg is one of those, but I don't know how it works in detail, sorry.
libinput-gestures depends on libinput, but again it's plugged on top and if it doesn't work, I'm not sure I can help much.

run sudo libinput-debug-events and do a swipe/pinch. If it's recognised by libinput, you'll see output on the commandline to that effect. But: this line in your data "B: PROP=9" suggests that your device is a semi-mt device (sudo evemu-record will print it in human-readable form).

Unfortunately, those semi-mt devices are unreliable and on those we don't do multi-finger detection beyond two-finger scrolling and tapping (iirc). basically, the data gets unreliably bad when there's more than one finger down. There may be room for doing some on your device, but it'd require some effort from you to identify what is actually possible and how far we can get.

Hi there :-)

Thank you very much for your reply and all the useful information. And for editing the correct Bug specs of course.

I switched back to libinput again. So the Wayland package of libinput should be used, right?
I'm not sure if i am getting the stuff regarding different compositors right.
Do you mean there are different compositor versions of libinput or just of input packages in general? (like synaptics, libinput ... )

After uninstalling synaptics and re-installing libinput again, "dpkg -l" is showing up this input package:
ii  xserver-xorg-input-libinp 0.18.0-1        amd64 
X.Org X server -- libinput input driver


That's correct, isn't it?
------------------------------------

I'd also like to clear things up a little bit.
Multitouch in sense of 2-Finger-Swipes is working fine out of the box, no matter if i use synaptics or libinput, each one without any additional gesture-mapping tool like touchegg oder libinput gestures.

Just Pinching and / or 3 or more - finger gestures aren't recognized.
Touchpad debug also is telling the coordinates absolutely fine on 2-finger swipes. 

But on pinching or 3+ - Finger swipes i'm getting following output:
libinput error: libinput bug: Event for missing capability CAP_GESTURE on device "AlpsPS/2 ALPS GlidePoint"


To be honest, it would already be great if i could at least map ALT+left/ALT+right (Browser back/forward) to the 2-finger horizontal swipe. 
In my case there's no need for horizontal scrolling using touchpad.

Do you think there could be a chance of at least realizing this?
For sure i'm absolutely happy to help with any information you need. At least i'll try as good as i can ;-)

Thank you very much for your support regarding my issue and of course your offer to further investigate this.

I'm happy to help with any information needed :-)

libinput is a library, it can be either used by the wayland compositor or by the xf86-input-libinput driver. Or commandline tools. Right now, all major compositors use libinput to process input events. Synaptics is an xorg driver alone, it sits next to xf86-input-libinput and the two are mutually exclusive, you have to pick one of the two for your touchpad device.

(In reply to nokodemus86 from comment #2)
> But on pinching or 3+ - Finger swipes i'm getting following output:
> libinput error: libinput bug: Event for missing capability CAP_GESTURE on
> device "AlpsPS/2 ALPS GlidePoint"

oops, that is indeed a bug. Please record a gesture that triggers that bug with sudo evemu-record and attach the output in a separate bug (as attachment, not as comment).

> To be honest, it would already be great if i could at least map
> ALT+left/ALT+right (Browser back/forward) to the 2-finger horizontal swipe. 
> In my case there's no need for horizontal scrolling using touchpad.
> 
> Do you think there could be a chance of at least realizing this?
> For sure i'm absolutely happy to help with any information you need. At
> least i'll try as good as i can ;-)

libinput only interprets and forwards the gestures, it doesn't actually handle them or convert them to semantic events. That's something that's up to the compositor (for global gestures) or the client/toolkit for local gestures. But - no chance of that happening in X, the bits in between are simply missing, sorry. It's a Wayland-only feature.

oh, and the error message indicates that your device has the gestures disabled (semi-mt) which explains why gestures won't work on your device, even in wayland. Two-finger scrolling is the only exception here.

(In reply to Peter Hutterer from comment #3)
> libinput is a library, it can be either used by the wayland compositor or by
> the xf86-input-libinput driver. Or commandline tools. Right now, all major
> compositors use libinput to process input events. Synaptics is an xorg
> driver alone, it sits next to xf86-input-libinput and the two are mutually
> exclusive, you have to pick one of the two for your touchpad device.

Ahh ... thank you for clarification. i think i'm starting to understand ... 

> oops, that is indeed a bug. Please record a gesture that triggers that bug
> with sudo evemu-record and attach the output in a separate bug (as
> attachment, not as comment).

Thanks for the hint. I created the outputs and attached them to a new bug:
https://bugs.freedesktop.org/show_bug.cgi?id=101327

> 
> libinput only interprets and forwards the gestures, it doesn't actually
> handle them or convert them to semantic events. That's something that's up
> to the compositor (for global gestures) or the client/toolkit for local
> gestures. But - no chance of that happening in X, the bits in between are
> simply missing, sorry. It's a Wayland-only feature.

Alright, i understand ... thank you for clarifying :-)

Ok, with that bug filed (Thanks!) I think all I can do here is close this one as WONTFIX - as said in comment 3 this is mostly a wayland feature and touchegg/libinput-gestures are out of my control here. Depending on bug 101327 we may re-open it if the device turns out to be useful enough, but don't pin your hope on that, sorry.

(In reply to Peter Hutterer from comment #6)
> Depending on bug
> 101327 we may re-open it if the device turns out to be useful enough, but
> don't pin your hope on that, sorry.

Hi :-)

No need to feel sorry about that. For now i think i can setup a pretty nice workaround regarding browser back/forward using one of those Firefox gesture addons. 

And probably, as you say, it's not the end of the story :-)
I'm happy to help as good as i can, if there's a way to give this touchpad it's superpowers  :-D

Thank you very much for your commitment regarding this issue ;-)