X.org server


X11 configuration directory.


Help us document errors that can be found in this log file, and what each error may mean and the appropriate solution.

Log file used by sddm for its interaction with the X.org server.

A major shortcoming of this file is that the log entries do not include any timestamp.

QXcbConnection: XCB error: 3 (BadWindow)

Sample error:

QXcbConnection: XCB error: 3 (BadWindow), sequence: 886, resource id: 39845897, major code: 18 (ChangeProperty), minor code: 0

Xorg.0.log: (EE) [drm] Failed to open DRM device for pci

The purpose of this wiki page is to collect all possible causes leading to the given error, and offer appropriate solutions in each case.

Two concurrent X11 sessions

Example /var/log/Xorg.0.log output:

[ 834.454] (EE) [drm] Failed to open DRM device for pci:0000:0b:00.0: -2
[ 834.454] (**) modeset(0): claimed PCI slot 11@0:0:0
[ 834.454] (II) modeset(0): using default device
[ 834.454] (WW) Falling back to old probe method for fbdev
[ 834.454] (II) Loading sub module "fbdevhw"


The ~/.xinitrc file is read when using the startx command or SLiM to login into a new X session.

See also:


The ~/.xprofile file is read when using login managers such as GDM, KDM or LightDM to start the X.org server.

It is for configuring and running applications before a window manager starts. e.g. a compositing manager.

.xprofile is a shell script. Thus it allows the same syntax as your shell.

Login managers

List of login managers sourcing ~/.xprofile

  • KDM
  • GDM
  • LXDM
  • SDDM
  • LightDM

List of login managers not directly sourcing ~/.xprofile:

Recover from invisible mouse due to misconfiguration

The linked wiki page describes a scenario whereby a misconfigured monitor width and refresh rate causes the mouse cursor to be completely invisible. Fortunately, it was possible to login (ssh, actually) as another user, and manually edit the configuration file. In that case, I was fortunate that I knew the exact time of when the problem started occurring, I had a working user, so I simply had to compare files changed at that time, between the working and non-working users.

KDE/X.org should allow the user to recover easily from such misconfiguration.

Black screen after starting KDE plasma session

In KDE Plasma 5, I started a new session and while the session was not completely loaded, I start to tab into another activity, but got a completely black screen, with only the white mouse pointer that I still could move on it.

I went into a TTY console and did:
ps aux | grep X
and kill the pid of the X process.
I was immediately brought back to the session login screen (sddm).
I logged in again and I saw an X window with the mention:
"Could not start ksmserver. Check your installation".

Syndicate content