如何将 TrackPoint 驱动程序从默认的 libinput 更改为较新的 libinput 或改回 Synaptics？

这款配备 Ubuntu 18.04 LTS 的 ThinkPad X390 上的 TrackPoint 动作跳动、滞后，无法用于精细的小动作。我已经确认这可能是一个软件问题，因为我已经用 TrackPoint 测试了一个外部键盘，它在 16.04 上很好，但在 18.04 上显示相同的问题。

我可以看到网上的评论表明将 libinput 切换到较新版本会有所帮助，而从 libinput 切换到 Synaptics 会有所帮助。后者怎么做？我可以从这里看到安装的可能性xserver-xorg-input-synaptics，但是，当我这样做时，我遇到了问题：

$ sudo apt install xserver-xorg-input-synaptics
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies.
 xserver-xorg-input-synaptics : Depends: xserver-xorg-core (>= 2:1.18.99.901)
E: Unable to correct problems, you have held broken packages.

$ sudo apt install xserver-xorg-core
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  libunity-gtk2-parser0 libunity-gtk3-parser0 libxatracker2 unity-gtk-module-common xinput
Use 'sudo apt autoremove' to remove them.
Suggested packages:
  xfonts-100dpi | xfonts-75dpi
The following packages will be REMOVED
  ubuntu-desktop ubuntu-mate-core ubuntu-mate-desktop ubuntu-unity-desktop xorg
  xserver-xorg-core-hwe-18.04 xserver-xorg-hwe-18.04 xserver-xorg-input-all-hwe-18.04
  xserver-xorg-input-libinput-hwe-18.04 xserver-xorg-input-synaptics-hwe-18.04
  xserver-xorg-input-wacom-hwe-18.04 xserver-xorg-video-all-hwe-18.04
  xserver-xorg-video-amdgpu-hwe-18.04 xserver-xorg-video-ati-hwe-18.04
  xserver-xorg-video-fbdev-hwe-18.04 xserver-xorg-video-intel-hwe-18.04
  xserver-xorg-video-nouveau-hwe-18.04 xserver-xorg-video-qxl-hwe-18.04
  xserver-xorg-video-radeon-hwe-18.04 xserver-xorg-video-vesa-hwe-18.04
  xserver-xorg-video-vmware-hwe-18.04
The following NEW packages will be installed
  xserver-xorg-core
0 to upgrade, 1 to newly install, 21 to remove and 11 not to upgrade.
Need to get 1,351 kB of archives.
After this operation, 5,808 kB disk space will be freed.
Do you want to continue? [Y/n] n
Abort.

如何进行？

编辑：根据@Pilot6 here的建议，我安装了xserver-xorg-input-synaptics-hwe-18.04（似乎已经成功）并检查了目录中的文件/usr/share/X11/xorg.conf.d：

10-amdgpu.conf
10-quirks.conf
10-radeon.conf
40-libinput.conf
51-synaptics-quirks.conf
70-synaptics.conf
70-wacom.conf

我删除了文件40-libinput.conf并重新启动，希望 Synaptics 驱动程序能够启动。它没有，导致键盘和 TrackPoint（和触摸板）没有响应。幸运的是，触摸屏和屏幕键盘可以替换文件40-libinput.conf。我不确定下一步该怎么做。

内容40-libinput.conf如下：

# Match on all types of devices but joysticks
Section "InputClass"
        Identifier "libinput pointer catchall"
        MatchIsPointer "on"
        MatchDevicePath "/dev/input/event*"
        Driver "libinput"
EndSection

Section "InputClass"
        Identifier "libinput keyboard catchall"
        MatchIsKeyboard "on"
        MatchDevicePath "/dev/input/event*"
        Driver "libinput"
EndSection

Section "InputClass"
        Identifier "libinput touchpad catchall"
        MatchIsTouchpad "on"
        MatchDevicePath "/dev/input/event*"
        Driver "libinput"
EndSection

Section "InputClass"
        Identifier "libinput touchscreen catchall"
        MatchIsTouchscreen "on"
        MatchDevicePath "/dev/input/event*"
        Driver "libinput"
EndSection

Section "InputClass"
        Identifier "libinput tablet catchall"
        MatchIsTablet "on"
        MatchDevicePath "/dev/input/event*"
        Driver "libinput"
EndSection

内容70-synaptics.conf如下：

# Example xorg.conf.d snippet that assigns the touchpad driver
# to all touchpads. See xorg.conf.d(5) for more information on
# InputClass.
# DO NOT EDIT THIS FILE, your distribution will likely overwrite
# it when updating. Copy (and rename) this file into
# /etc/X11/xorg.conf.d first.
# Additional options may be added in the form of
#   Option "OptionName" "value"
#
Section "InputClass"
        Identifier "touchpad catchall"
        Driver "synaptics"
        MatchIsTouchpad "on"
# This option is recommend on all Linux systems using evdev, but cannot be
# enabled by default. See the following link for details:
# http://who-t.blogspot.com/2010/11/how-to-ignore-configuration-errors.html
      MatchDevicePath "/dev/input/event*"
EndSection

Section "InputClass"
        Identifier "touchpad ignore duplicates"
        MatchIsTouchpad "on"
        MatchOS "Linux"
        MatchDevicePath "/dev/input/mouse*"
        Option "Ignore" "on"
EndSection

# This option enables the bottom right corner to be a right button on clickpads
# and the right and middle top areas to be right / middle buttons on clickpads
# with a top button area.
# This option is only interpreted by clickpads.
Section "InputClass"
        Identifier "Default clickpad buttons"
        MatchDriver "synaptics"
        Option "SoftButtonAreas" "50% 0 82% 0 0 0 0 0"
        Option "SecondarySoftButtonAreas" "58% 0 0 15% 42% 58% 0 15%"
EndSection

# This option disables software buttons on Apple touchpads.
# This option is only interpreted by clickpads.
Section "InputClass"
        Identifier "Disable clickpad buttons on Apple touchpads"
        MatchProduct "Apple|bcm5974"
        MatchDriver "synaptics"
        Option "SoftButtonAreas" "0 0 0 0 0 0 0 0"
EndSection