Bug 92622

Summary: Two-finger scrolling - inverted order of fingers
Product: xorg Reporter: Piotr Piastucki <piastucki>
Component: Input/synapticsAssignee: Peter Hutterer <peter.hutterer>
Status: RESOLVED FIXED QA Contact:
Severity: normal    
Priority: medium CC: peter.hutterer
Version: unspecified   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:

Description Piotr Piastucki 2015-10-22 22:25:56 UTC
After upgrading from Ubuntu 15.04 (synaptics 1.8.1) to 15.10 (synaptics 1.8.2) I noticed a problem with two-finger scrolling on my Asus laptop (touchpad recognized as elantech). Basically the order in which fingers need to be placed on the touchpad to use two-finger scrolling is inverted and thus makes the feature hard to use:
1) place 1st finger on the touchpad
2) place 2nd finger on the touchpad
3) I have to move the 1st finger now to scroll in 1.8.1 0 this should be really the 2nd finger as it used to be
Apart from weird order of finger placement the scrolling works fine both horizontally and vertically, unfortunately the order is very unnatural.
Comment 1 Peter Hutterer 2015-10-25 21:36:16 UTC
Does ubuntu have any patches on top of 1.8.1 or 1.8.2? If not, can you please try to bisect which commit broke this? Thanks

There are only 4 commits and none look like they could've triggered this.
Comment 2 Piotr Piastucki 2015-10-26 07:09:58 UTC
Ubuntu package can be found here:
https://launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/1.8.2-1ubuntu1 
along with the list of Debian patches and the actual diff:
http://launchpadlibrarian.net/211589436/xserver-xorg-input-synaptics_1.8.1-1ubuntu1_1.8.2-1ubuntu1.diff.gz
http://launchpadlibrarian.net/211589407/xserver-xorg-input-synaptics_1.8.2-1ubuntu1_source.changes

Let me know if any further info is needed. 
In case it is not enough I will try to build the package from source and bisect.
Comment 3 Peter Hutterer 2015-10-26 07:20:44 UTC
hmm, that's a few patches there. I'd say try the upstream vanilla 1.8.2 package first if that has the same issue. If so, then you can bisect. Thanks
Comment 4 Piotr Piastucki 2015-10-26 17:32:14 UTC
I do not think it is related to Debian patches.
I tried the following:
1) install 1.8.1 from Debian https://packages.debian.org/jessie/xserver-xorg-input-synaptics    WORKS FINE
2) install 1.8.2 from Debian https://packages.debian.org/sid/xserver-xorg-input-synaptics    DOES NOT WORK PROPERLY
3) overwrite /usr/lib/xorg/modules/input/synaptics_drv.so with the one from 1.8.1   WORKS FINE
4) download synaptics sources and build locally - 
http://ftp.x.org/pub/individual/driver/xf86-input-synaptics-1.8.2.tar.bz2
5) overwrite /usr/lib/xorg/modules/input/synaptics_drv.so with the one built in 4) DOES NOT WORK PROPERLY

I will try to bisect now
Comment 5 Piotr Piastucki 2015-10-26 18:37:13 UTC
More findings:
1) master i.e. git clone http://anongit.freedesktop.org/git/xorg/driver/xf86-input-synaptics.git, build locally, overwrite /usr/lib/xorg/modules/input/synaptics_drv.so WORKS FINE 
2) 1.8 branch i.e. git clone -b synaptics-1.8-branch http://anongit.freedesktop.org/git/xorg/driver/xf86-input-synaptics.git , build locally, overwrite /usr/lib/xorg/modules/input/synaptics_drv.so DOES NOT WORK PROPERLY
3) reverting to 1.8.1 i.e. git reset --hard d50c4bab8ae2836a0f38b29a5d22be2e950e4d08 DOES NOT HELP
4) bisecting master reveals that the issue is fixed by http://cgit.freedesktop.org/xorg/driver/xf86-input-synaptics/commit/?id=ec0901e5f81d9cad6cc8bbdcb5ea075009c13de5

Cherry-picking ec0901e5f81d9cad6cc8bbdcb5ea075009c13de5 into 1.8 branch fixes the problem.

So it might be actually the case that there was a Debian patch that addressed the issue in 1.8.1 and no longer works in 1.8.2.

Question - any chances you can include the fix in 1.8 branch?
Comment 6 Peter Hutterer 2015-10-28 04:24:12 UTC
done, commit 3e7508ac087028f8f8e116f5279dad1ebcdc58e6 on the 1.8 branch. I'll do a release in the next couple of days if nothing else comes in.

thanks for bisecting, that made it a lot easier for me :)
Comment 7 Piotr Piastucki 2015-10-28 12:45:59 UTC
Thanks!
Comment 8 Peter Hutterer 2015-11-01 23:49:59 UTC
for the archives, synaptics 1.8.3 was released today and includes this patch:
http://lists.x.org/archives/xorg-announce/2015-November/002652.html

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