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I’ve been annoyed for a while that Firefox only supports the kind of two finger scrolling where moving the fingers on the touch pad a decent amount emits a scroll wheel event. I just now found out that if you start Firefox with the environment variable MOZ_USE_XINPUT2 set to 1, it will use xinput 2, and support actual smooth touch pad scrolling.

I know this works for Firefox 55 or newer, but don’t know the earliest version which supports it. I assume it will be enabled by default at some point, but it isn’t yet in Firefox 58 (the current nightly).

  1. Run this command:

    echo MOZ_USE_XINPUT2=1 | sudo tee /etc/profile.d/use-xinput2.sh

  2. Log out and back in.

  3. Firefox should now use xinput 2.

  4. (optional) Open Firefox and go to about:preferences -> Advanced (or about:preferences -> Browsing for Firefox Nightly), and uncheck “Use smooth scrolling”. This disables the old style “smooth scrolling”, which just causes an annoying delay when using xinput2 style scrolling imo.

On a separate note: it’s really encouraging to see Firefox finally become a great browser. Firefox 57 is looking to be an amazing release.


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    PSA for FreeBSD -CURRENT users: you can get that pixel precise scrolling too :)

    Build the kernel with options EVDEV_SUPPORT, set sysctl kern.evdev.rcpt_mask=12, build xorg-server with udev support, install xf86-input-libinput, enjoy.

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      Note that if you use xinput2 and synclient to reverse scrolling, it won’t be reversed. You have to remap the 4 5 buttons instead. Discovered this when chromium switched to xinput2 a while back. (Details fuzzy and subject to wrongness.)

      (Looking again at my .xinitrc, I believe I did get the details backwards. You must use a negative scroll delta instead of remapping buttons.)

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        Just noticed a typo; it should be echo export MOZ_USE_XINPUT2=1 | sudo tee /etc/profile.d/use-xinput2.sh. I can’t seem to edit the post.

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          Heh. That’s why it’s better to write the actual content elsewhere and just link to it here ;-p