I have no touchpad connected to my PC, and if I open the touchpad KCM, a red error bar pops up. I suppose the bar should say something like "no touchpad found", but it's empty. The widgets in the KCM are locked, so I can't change anything (which is, of course, right). Using GDB, I found out that "m_errorString" in backends/x11/xlibbackend.h isn't set, because XlibSynapticsBackend::XlibSynapticsBackend returns on line 155, without setting a error string. Reproducible: Always Steps to Reproduce: 1. Do not have a touchpad 2. Open the touchpad KCM Actual Results: The red error bar is empty Expected Results: The red error bar says something like "No Touchpad found" The xf86-input-synaptics package is installed.
Thanks for the report, debugging and the analysis. XlibSynapticsBackend::XlibSynapticsBackend:155 certainly looks like could issue the error message.
Git commit 3f2e6bd31e0cd7355f95450cdc185e4d37ed2c16 by Rajeesh K Nambiar. Committed on 27/06/2015 at 11:58. Pushed by knambiar into branch 'master'. Fix touchpad backend initialization. Libinput driver, even when unistalled was leaving 'Libinput Tapping Enabled' atom active (xlsatoms | grep -i tap). Mutter/Clutter/Gtk+ were causing this, as noted in https://bugzilla.redhat.com/show_bug.cgi? id=1199825. This caused the non-existent libinput backend initialization resulting in 'No touchpad found' error even when synaptics driver was installed. Fix this by checking backend instantiation errors. Related: bug 344958 REVIEW: 124172 FIXED-IN: 5.4.0 M +13 -7 kcms/touchpad/src/backends/x11/xlibbackend.cpp http://commits.kde.org/plasma-desktop/3f2e6bd31e0cd7355f95450cdc185e4d37ed2c16
Thanks, it works now