<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Lenovo P50 - Slow fine touchpad movement makes it jump (bug 2)" href="https://bugs.freedesktop.org/show_bug.cgi?id=105963#c13">Comment # 13</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Lenovo P50 - Slow fine touchpad movement makes it jump (bug 2)" href="https://bugs.freedesktop.org/show_bug.cgi?id=105963">bug 105963</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 was typed in response to <a href="show_bug.cgi?id=105963#c8">comment #8</a>, but bugzilla didn't take it first time round] Also look into <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - Acceleration still too fast with slow and slow-medium finger movements" href="show_bug.cgi?id=101139">bug 101139</a>, that is the current bug for the "way too fast" behaviour. As for debugging this in general: touchpad_accel_profile_linear() is the acceleration profile and the returned factor is applied to the deltas. The threshold and incline are affected by the configured speed, see touchpad_accelerator_set_speed() which is called when you change the property. Note that if you're using libinput debug-events or any other tools, the context is *not* the one your X server has, it's always a new context and changes don't go across. Think of it as two different processes reading the same byte stream, you can change how you process data in one process but the other one still receives the unmodified byte stream and is thus unaffected. So any changes in X don't affect libinput debug-events and vice versa. libinput debug-gui has a hidden feature, cursor keys up/down change the pointer acceleration by ±0.1 with each press. That's going to be helpful for testing because you see the immediate effects on the cursor. Also note that in calculate_acceleration() we're using simpson's rule to smooth things a bit. So that may affect things a bit as well. > I think sharing a flag with other quirks causes problems It shouldn't, the flags are just that and libinput doesn't care about them beyond the usual handling. That particular T450 flag is only used in one place, so re-using it is safe.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>