Comment 0 for bug 1774242

/usr/share/X11/xorg.conf.d/70-wacom.conf as shipped, has this:

Section "InputClass"
        Identifier "Wacom touchscreen class"
        MatchProduct "Wacom|WACOM|PTK-540WL|ISD-V4"
        MatchDevicePath "/dev/input/event*"
        MatchIsTouchscreen "true"
        Driver "wacom"
EndSection

The result is that on my Yoga 920, in a plain X11 session (running openbox in my case), the touchscreen acts like a broken mouse: there is no multi-touch capability in Qt Quick applications, and clicking isn't quite right either. I also verified it with Peter Hutterer's old cairo-based mt-touch test program.

I suspect we will get some users mistakenly writing up Qt bugs about this if you don't ship a fix. (Seems to me that already happened at least once, actually.)

Yes, the touchscreen is made by Wacom, but wacom_drv.so has historically been only for Wacom tablets and in-screen stylus digitizers, and IMO that continues to be the case. libinput is a much better choice of driver for this hardware (so is evdev for that matter), so I changed it to Driver "libinput" and got it working. (Wayland uses libinput, so in a wayland session, touch already works fine in Qt apps on this hardware.)

I'm one of the Qt Quick maintainers, most concerned with touch handling, and I've also written some of the Qt xcb code for dealing with XInput touch and tablet devices. So if you think that there's something wrong with Qt, such that it should still work anyway to use a wacom driver for a Wacom touchscreen, let me know. These AES devices are still new to me (that's why I got a Yoga, to try it out).

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xserver-xorg-input-wacom 1:0.36.1-0ubuntu1 [modified: usr/share/X11/xorg.conf.d/70-wacom.conf]
ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17
Uname: Linux 4.15.0-22-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
Date: Wed May 30 19:40:51 2018
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
MachineType: LENOVO 80Y7
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.15.0-22-generic root=ZFS=rpool/ROOT/ubuntu ro
SourcePackage: xf86-input-wacom
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/22/2018
dmi.bios.vendor: LENOVO
dmi.bios.version: 5NCN38WW
dmi.board.asset.tag: NO Asset Tag
dmi.board.name: LNVNB161216
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40709 WIN
dmi.chassis.asset.tag: NO Asset Tag
dmi.chassis.type: 31
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo YOGA 920-13IKB
dmi.modalias: dmi:bvnLENOVO:bvr5NCN38WW:bd02/22/2018:svnLENOVO:pn80Y7:pvrLenovoYOGA920-13IKB:rvnLENOVO:rnLNVNB161216:rvrSDK0J40709WIN:cvnLENOVO:ct31:cvrLenovoYOGA920-13IKB:
dmi.product.family: YOGA 920-13IKB
dmi.product.name: 80Y7
dmi.product.version: Lenovo YOGA 920-13IKB
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.91-2
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.0~rc5-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.0~rc5-1ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.19.6-1ubuntu4
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.5-1ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.0.1-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2