GNOME Bugzilla – Bug 719406
impossible to enable two-finger scroll emulation
Last modified: 2013-12-13 18:04:59 UTC
After the fix of bug 702858, it's no longer possible to use two-finger scrolling emulation on touchpads which don't support multi-finger touch detection. The problem is that now if the touchpad doesn't report multi-touch capability, g-s-d declares two-finger scroll impossible and forcibly disables it, and turns on edge scroll instead. Previously (in Fedora 19 / gnome 3.8 and before) I could drop an extra xorg.conf file to enable it: # cat /etc/X11/xorg.conf.d/50-touchpad-two-finger-scroll.conf Section "InputClass" Identifier "touchpad two finger scroll" MatchIsTouchpad "on" MatchProduct "SynPS/2 Synaptics TouchPad" Option "EmulateTwoFingerMinZ" "30" Option "HorizTwoFingerScroll" "true" Option "VertTwoFingerScroll" "true" EndSection but it isn't honored since upgrade with a message (gnome-settings-daemon:1156): mouse-plugin-WARNING **: Two finger scroll is not supported by SynPS/2 Synaptics TouchPad and the scroll is set to edge.
Created attachment 263595 [details] [review] allow setting two finger scroll also when we have emulation (g-c-c)
Created attachment 263596 [details] [review] allow setting two finger scroll also when we have emulation (g-s-d)
However not sure whether EmulateTwoFingerMinZ property should be also changed and whether is there any suitable value for it across all touchpads... Romand, could you prove the patches please?
If the emulation doesn't work with default EmulateTwoFingerMinZ and EmulateTwoFingerMinW values and there isn't any universal value for it, we can't probably use the patches, because it will cause another bug reports, that two finger scroll doesn't work (Bug 702858)...
I don't have access to build environment ATM so I can't test your patches now. They look like solving *my* problem in that they make g-s-d not override my settings. However, there's exactly the problem you mention in comment 4: the default value of EmulateTwoFingerMinZ is fairly big (280 on my T500) so that, without explicitly setting it to a much lower value (I use 30) the emulation doesn't work. With your patch from comment 1 the "two finger stcroll" toggle will not be disabled, so people would turn it on and expect it to just work, but it won't without extra tweaks; I'm not sure how universal the value of 30 is. AFAICT it won't break people who want edge scrolling because if two-finger toggle is off g-s-d explicitly disables two-finger scrolling and enables edge scrolling. Perhaps, as a first approximation, one can add settings corresponding to EmulateTwoFingerMinZ and EmulateTwoFingerMinW with default values of, say, 30 and 7, but only expose them in the UI if there's demand; meanwhile people who need that would be able to control them with "gsettings" command or equivalent.
I'm not sure whether we actually want to do that. If EmulateTwoFingerMinZ needs to be changed for it to be useful, then we can choose not to support it. Roman could then use this script to avoid the mouse g-s-d plugin overwriting his Xorg settings: https://git.gnome.org/browse/gnome-settings-daemon/tree/plugins/common/input-device-example.sh Peter, is two-finger emulation supposed to be working out of the box?
Actually, this is a duplicate of bug 625163. There's a complete history of the setting in that bug. I think it would be best if you disabled the mouse settings for that device using the above script. *** This bug has been marked as a duplicate of bug 625163 ***