Bug 349214

Summary:	"no touchpad found" error message is empty
Product:	[Applications] systemsettings	Reporter:	David Kahles <david.kahles96>
Component:	kcm_touchpad	Assignee:	Plasma Bugs List <plasma-bugs>
Status:	RESOLVED FIXED
Severity:	normal	CC:	david.kahles96, rajeeshknambiar
Priority:	NOR
Version:	5.17.5
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:	http://commits.kde.org/plasma-desktop/3f2e6bd31e0cd7355f95450cdc185e4d37ed2c16	Version Fixed In:	5.4.0

Description David Kahles 2015-06-15 23:51:04 UTC

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.

Comment 1 Rajeesh K V 2015-06-17 16:41:41 UTC

Thanks for the report, debugging and the analysis. XlibSynapticsBackend::XlibSynapticsBackend:155 certainly looks like could issue the error message.

Comment 2 Rajeesh K V 2015-06-27 11:58:27 UTC

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

Comment 3 David Kahles 2015-06-29 14:07:55 UTC

Thanks, it works now