<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - Two finger scrolling isn't smooth" href="https://bugs.freedesktop.org/show_bug.cgi?id=89683#c1">Comment # 1</a> on <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - Two finger scrolling isn't smooth" href="https://bugs.freedesktop.org/show_bug.cgi?id=89683">bug 89683</a> from <a class="email" href="mailto:peter.hutterer@who-t.net" title="Peter Hutterer <peter.hutterer@who-t.net>"> Peter Hutterer</a> <pre>This is weird. In the recording, your fingers move in opposite directions for a number of events. In libinput, we average the movement of all fingers so the movement cancels out. The jumps come from when the fingers move in the same direction. I put printf statements in libinput before replaying and this is the output: ---- tp_gesture_post_twofinger_scroll:123 Touch 0 0.00/10.42 Touch 1 0.00/-10.42 Delta 0.00/0.00 ---- Delta after filter: 0.00/0.00 ---- tp_gesture_post_twofinger_scroll:123 Touch 0 0.00/9.92 Touch 1 0.00/-9.92 Delta 0.00/0.00 ---- Delta after filter: 0.00/0.00 ---- tp_gesture_post_twofinger_scroll:123 Touch 0 0.00/9.92 Touch 1 0.00/-9.92 Delta 0.00/0.00 ---- Delta after filter: 0.00/0.00 ---- tp_gesture_post_twofinger_scroll:123 Touch 0 0.00/9.43 Touch 1 0.00/-9.43 Delta 0.00/0.00 ---- Delta after filter: 0.00/0.00 ---- tp_gesture_post_twofinger_scroll:123 Touch 0 0.00/8.43 Touch 1 0.00/19.35 Delta 0.00/13.89 ---- Delta after filter: 0.00/5.62 ---- tp_gesture_post_twofinger_scroll:123 Touch 0 0.00/7.94 Touch 1 0.00/49.61 Delta 0.00/28.78 ---- Delta after filter: 0.00/13.06 That's the first couple of events, up to probably E: 0.389343 in the recording. This repeats itself, with the jumps in between where the delta goes to something normal. The movements aren't always identical, there is a later set like this: ---- tp_gesture_post_twofinger_scroll:123 Touch 0 0.00/9.43 Touch 1 0.00/-7.44 Delta 0.00/0.99 ---- Delta after filter: 0.00/0.35 ---- tp_gesture_post_twofinger_scroll:123 Touch 0 0.00/8.43 Touch 1 0.00/-8.43 Delta 0.00/0.00 ---- Delta after filter: 0.00/0.00 ---- tp_gesture_post_twofinger_scroll:123 Touch 0 0.00/7.44 Touch 1 0.00/-7.44 Delta 0.00/0.00 This looks very odd. Unless you're doing this intentionally this would point at some hw or firmware issue. Or a kernel bug. Can you confirm that you're moving the fingers in the same direction here?</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>