I installed Arch Linux on an Asus C201 Chromebook using this guide (the debian and fedora guides for the notebook didn't work for me and resulted in a black screen).This worked well more or less out of the box until I upgraded the system using pacman -Syu. Now the touchpad doesn't work properly anymore:Behaviour description (go to Update below for a miracle solution)Trying to move the cursor with a single finger seems to trigger scrolling. I can very slowly move the cursor when using one finger and sort of scratch the touchpad with the nail. But this really only moves the cursor a little.I can also press the touchpad and then move the cursor in which case the cursor moves and highlights.What I tried so farI double checked /etc/X11/xorg.conf.d/70-synaptics.conf and am using the configuration shown in the arch wiki as an example. I also had a copy of the pre-upgrade synaptics.conf but this didn't change the behavior either.I uninstalled and reinstalled xf86-input-synapticssudo dmesg | grep elan shows the following two lines:[   1.6 ] i2c 4-0015: Driver elan_i2c requests probe deferral[ 408.6 ] elan_i2c 4-0015: invalid report id data (ff)SummaryBased on the touchpad behaviour, it feels that the upgrade caused havoc with the touchpad configuration. However, the configuration file seems to be ok. Reinstallting the touchpad driver doesn't seem to have an impact.Any other ideas of what I could do?/etc/X11/xorg.conf.d/50-synaptics.confI uninstalled and reinstalled the synaptics driver and this is the config file:Section InputClass    Identifier touchpad    Driver synaptics    MatchIsTouchpad on        Option TapButton1 1        Option TapButton2 3        Option TapButton3 2        Option VertEdgeScroll on        Option VertTwoFingerScroll on        Option HorizEdgeScroll on        Option HorizTwoFingerScroll on        Option CircularScrolling on        Option CircScrollTrigger 2        Option EmulateTwoFingerMinZ 40        Option EmulateTwoFingerMinW 8        Option CoastingSpeed 0        Option FingerLow 30        Option FingerHigh 50        Option MaxTapTime 125 EndSectionThe file I used before the upgrade only had the changes shown in the arch wiki as a sample configuration.synclient -lsynclient -l returns:Parameter settings:    LeftEdge                = 120    RightEdge               = 2884    TopEdge                 = 88    BottomEdge              = 1554    FingerLow               = 30    FingerHigh              = 50    MaxTapTime              = 125    MaxTapMove              = 150    MaxDoubleTapTime        = 100    SingleTapTimeout        = 180    ClickTime               = 100    EmulateMidButtonTime    = 0    EmulateTwoFingerMinZ    = 40    EmulateTwoFingerMinW    = 8    VertScrollDelta         = 68    HorizScrollDelta        = 68    VertEdgeScroll          = 1    HorizEdgeScroll         = 1    CornerCoasting          = 0    VertTwoFingerScroll     = 1    HorizTwoFingerScroll    = 1    MinSpeed                = 1    MaxSpeed                = 1.75    AccelFactor             = 0.0584283    TouchpadOff             = 0    LockedDrags             = 0    LockedDragTimeout       = 5000    RTCornerButton          = 0    RBCornerButton          = 0    LTCornerButton          = 0    LBCornerButton          = 0    TapButton1              = 1    TapButton2              = 3    TapButton3              = 2    ClickFinger1            = 1    ClickFinger2            = 3    ClickFinger3            = 2    CircularScrolling       = 1    CircScrollDelta         = 0.1    CircScrollTrigger       = 2    CircularPad             = 0    PalmDetect              = 0    PalmMinWidth            = 10    PalmMinZ                = 200    CoastingSpeed           = 0    CoastingFriction        = 50    PressureMotionMinZ      = 30    PressureMotionMaxZ      = 160    PressureMotionMinFactor = 1    PressureMotionMaxFactor = 1    GrabEventDevice         = 0    TapAndDragGesture       = 1    AreaLeftEdge            = 0    AreaRightEdge           = 0    AreaTopEdge             = 0    AreaBottomEdge          = 0    HorizHysteresis         = 17    VertHysteresis          = 17    ClickPad                = 1    RightButtonAreaLeft     = 1502    RightButtonAreaRight    = 0    RightButtonAreaTop      = 1346    RightButtonAreaBottom   = 0    MiddleButtonAreaLeft    = 0    MiddleButtonAreaRight   = 0    MiddleButtonAreaTop     = 0    MiddleButtonAreaBottom  = 0UpdateI found this thread on an arch forum which looked pretty close to my problem. The proposed solution was to downgrade xf86-input-synaptics to 1.8.3-4. This mostly solved the issues, the touchpad was usable in general though I would have needed to change some of the sensitivity settings.When I tried to use libinput before instead of synaptics, the touchpad didn't work at all, however I never removed the synaptics xorg.conf file as suggested by @mattia.b89. So I uninstalled synaptics again (this is after downgrading it) and removed the xorg.conf file:From the moment I removed the xorg.conf file and synaptics, after reboot, the touchpad was working, however scrolling and multitouch didn't work. I don't understand that at all..... at this point neither synaptics nor libinput was installed.I then installed libinput and now scrolling and multitouch works as intended. I haven't tried to get tapping to work yet, but in any case it is functional now.This all feels like magic a bit. I'll leave the bounty open for a little bit just to see if someone can explain what just happened. In any case thanks to @mattia.b89 and @C.W. for helping with this.
Touchpad not working properly after upgrade - Arch on Chromebook
arch linux;touchpad;chrome book;synaptic
switch to xf86-input-libinput because it is simpler and based on a more modern codePS: I know, my statement could not be useful without quotation/be thought as wrong, but you can easily find many sources on internet that talk about it...