Bug 103567

Summary:	[regression] Middle-click emulation broken
Product:	Wayland	Reporter:	Sami B. <spidermario>
Component:	libinput	Assignee:	Wayland bug list <wayland-bugs>
Status:	RESOLVED INVALID	QA Contact:
Severity:	normal
Priority:	medium	CC:	peter.hutterer
Version:	unspecified
Hardware:	x86-64 (AMD64)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Sami B. 2017-11-03 22:59:59 UTC

Hi,

I have middle-click emulation enabled in Cinnamon (although `sudo libinput list-devices` says that it is not; is it because it doesn’t show per-user settings or does Cinnamon use some other mechanism?).

It used to work perfectly, but I recently upgraded libinput from 1.8.3 and 1.9.1, and since then, it often gets “stuck”, meaning that subsequent left clicks will be considered middle clicks until I right click again to “unstick” it (or occasionally the other way around, possibly depending on which button I happen to hit first when emulating the middle click).

After downgrading to 1.8.3 again and rebooting, the issue goes away completely.

I had a look through the recent messages on the mailing list and it looks like this patch could be the culprit, but I am far from being 100% sure: https://lists.freedesktop.org/archives/wayland-devel/2017-October/035551.html

Thanks.

Comment 1 Sami B. 2017-11-04 10:56:54 UTC

Sorry, I realized that the patch I pointed to has not been merged yet.

I will try to bisect the issue later today.

Comment 2 Sami B. 2017-11-04 15:12:07 UTC

I haven’t been able to reproduce the issue. I suppose that it was the reboot that fixed the issue, with nothing to do with libinput.

Sorry for the noise.

Comment 3 Sami B. 2017-11-04 17:57:14 UTC

Someone on IRC just mentioned a very similar problem (left click -> buttonpress 1, buttonrelease 1; right click -> buttonpress 3, buttonrelease 3; left+right click -> buttonpress 1, buttonpress 3, buttonrelease 1) which was solved by unplugging the mouse and plugging it back in, so there might be a recent regression after all. If it happens to me again, I will try to use evemu to capture the problem.

Comment 4 Sami B. 2017-11-04 18:06:12 UTC

Could the problem be caused by libinput entering “debounce mode” for the device, following https://github.com/wayland-project/libinput/commit/55d1bb1217388e99b9405654c14881a9ebf8f880?

Comment 5 Peter Hutterer 2017-11-06 05:54:27 UTC

could be, though button bouncing generally stops when the button numbers are mixed. I recommend running libinput debug-events --verbose because it'll print when debouncing activates.

Run evemu-record with the --autorestart flag, that way you can leave it running with a short pause to get a new recording. It'll help produce a short recording to reproduce the issue.

Also, libinput-debug-events can be run from the build tree without the need for restarting the session etc, making it ideal for e.g. bisecting.

Comment 6 Peter Hutterer 2017-11-15 04:07:19 UTC

probably a dupe of bug 103636. There's a patchset+branch to rework the debouncing code here: https://lists.freedesktop.org/archives/wayland-devel/2017-November/035782.html

please give that one a test, thanks.

Comment 7 Peter Hutterer 2017-12-13 05:51:31 UTC

closing after a month in needinfo

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