Is there any possibility of enabling this soon? Out-of-the-box Firefox is unusable with touchscreens, and as touchscreens become more common (e.g. I just upgraded my laptop to one that has a touchscreen), having this enabled quickly becomes quite important for a large number of users. Also, https://bugzilla.mozilla.org/show_bug.cgi?id=1182700 was just fixed in Kwin, and AFAIK that was the last blocker of this bug.

Also, AFAIK, Fedora enables MOZ_USE_XINPUT2 by default for these reasons, so apparently it's not too buggy :P

After some more thinking, it would probably make sense to enable it by default but disable it for KWin < 1.19.3, so those users don't get hit by the bug.

(In reply to QwertyChouskie from comment #13)

Also, https://bugzilla.mozilla.org/show_bug.cgi?id=1182700 was just fixed in Kwin, and AFAIK that was the last blocker of this bug.

Based on comment 10, it sounds like Gnome is affected as well, and the issue is not fixed there?

I am unable to reproduce using the steps in https://bugzilla.gnome.org/show_bug.cgi?id=750994#c0 with my laptop's touchpad, tested on Gnome Shell 3.36 (Ubuntu 20.04). I tried the same steps with FF and also can not reproduce it there. I suspect the bug was mitigated/had its impact lessened (perhaps unintentionally) in Gnome at some point, which then left the issue for KDE users (as per most of the comments in https://bugzilla.mozilla.org/show_bug.cgi?id=1182700).

(Also FYI, the KWin fix was just backported to the 5.18 series, so it should be fixed in the next 5.18.x point release, meaning Ubuntu 20.04 and its derivatives should get this fix soon.)

Martin, WDYT? Based on the above info, should we enable XInput 2 for KWin >= 5.19.3 (and >= 5.18.next)? How about other window managers?

(In reply to Botond Ballo [:botond] from comment #18)

Martin, WDYT? Based on the above info, should we enable XInput 2 for KWin >= 5.19.3 (and >= 5.18.next)? How about other window managers?

Fedora has used XINPUT2 by default for five years and I don't have any reports so I guess it's okay to enable it for recent systems, at least for KDE/Gnome.

(In reply to Martin Stránský [:stransky] from comment #19)

Fedora has used XINPUT2 by default for five years and I don't have any reports so I guess it's okay to enable it for recent systems, at least for KDE/Gnome.

Thanks!

(As this bug is assigned to you, I assume you'll write the enablement patch, but please let me know if you'd like me to.)

https://hg.mozilla.org/mozilla-central/rev/6c7f2177e485

Let's revert that in Bug 1660212.

This bug should probably be reopened since the change was completely reverted.

(In reply to Mathew Hodson from comment #25)

This bug should probably be reopened since the change was completely reverted.

Confirmed. Need to set environment variable in Debian 11 with Firefox 78.12.0esr (64 bit).