Bug 91081 - AlpsPS/2 ALPS DualPoint TouchPad two finger scrolling is jumpy
Summary: AlpsPS/2 ALPS DualPoint TouchPad two finger scrolling is jumpy
Alias: None
Product: Wayland
Classification: Unclassified
Component: libinput (show other bugs)
Version: unspecified
Hardware: Other All
: medium normal
Assignee: Wayland bug list
QA Contact:
Depends on:
Reported: 2015-06-24 11:15 UTC by Ignacio Casal Quinteiro
Modified: 2015-08-13 00:01 UTC (History)
2 users (show)

See Also:
i915 platform:
i915 features:

evemu log (81.49 KB, text/plain)
2015-06-24 11:17 UTC, Ignacio Casal Quinteiro

Description Ignacio Casal Quinteiro 2015-06-24 11:15:33 UTC
So out of curiosity I tried today with the two finger scrolling, and trying to scroll a document in gedit is jumpy as in not very smooth. See though that I am currently using the package from here:

See https://bugs.freedesktop.org/show_bug.cgi?id=90990 for reference.
Comment 1 Ignacio Casal Quinteiro 2015-06-24 11:17:05 UTC
Created attachment 116688 [details]
evemu log

Here you can find the log when scrolling with 2 fingers
Comment 2 Peter Hutterer 2015-07-14 00:22:32 UTC
this is a semi-mt touchpad where the resolution just isn't there when two fingers are on the touchpad. I'm almost tempted to disable two-finger scrolling on those pads.

have a look at the value jumps between the various ABS_MT_POSITION_X/Y coordinates, they are huge.
Comment 3 Ignacio Casal Quinteiro 2015-07-14 06:19:55 UTC
I wonder if it is a bug in the driver since on windows two finger scrolling is also the default way. Though I always preferred the edge one.
Comment 4 Peter Hutterer 2015-07-15 00:10:08 UTC
does the two-finger scrolling work fine in Windows?
Comment 5 Ignacio Casal Quinteiro 2015-07-15 06:27:49 UTC
yeah, on windows the two finger one seems to work fine. See also that for linux the driver was reverse engineered
Comment 6 Peter Hutterer 2015-07-22 05:23:53 UTC
judging by Hans' comments this should be fixed with recent kernels, any chance you can try that? looks like v4.2-rc1 has all the changes.
Comment 7 Peter Hutterer 2015-08-12 04:25:16 UTC
Comment 8 Ignacio Casal Quinteiro 2015-08-12 06:22:01 UTC
Peter, sorry for not replying. It seems f22 still has 4.1 so I'd rather wait for the update before messing up with the kernel.
Comment 9 Peter Hutterer 2015-08-13 00:01:45 UTC
ok, thanks. I'll close the bug for now, otherwise I keep clicking on it wondering why it's still open :)

As I said in Comment 6, the patches to fix this should've gone into v4.2-rc1, so if it the problem still occurs with that kernel, please reopen this bug.

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