xfsettingsd crashes after disconnecting from screen and ac

[Shuhao]

I can reproduce this on my thinkpad 100% of the time:

1. Connect to a second monitor using extend.
2. xrandr command to set to internal monitor only
3. disconnect the monitor
4. disconnect the power
5. wait about 5 seconds

Running xfsettingsd --no-daemon gives me the following:

(xfsettingsd:3271): xfsettingsd-CRITICAL **: Stored Xfconf properties disable all outputs, aborting.
The program 'xfsettingsd' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadRRCrtc (invalid Crtc parameter)'.
  (Details: serial 1264 error_code 148 request_code 140 minor_code 21)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

Not sure how to debug further.

Maybe related to https://bugs.launchpad.net/ubuntu/+source/xfce4-settings/+bug/1382741

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: xfce4-settings 4.11.3-0ubuntu2
ProcVersionSignature: Ubuntu 3.16.0-23.30-generic 3.16.4
Uname: Linux 3.16.0-23-generic x86_64
ApportVersion: 2.14.7-0ubuntu7
Architecture: amd64
CurrentDesktop: XFCE
Date: Sat Oct 18 21:42:08 2014
InstallationDate: Installed on 2013-07-08 (467 days ago)
InstallationMedia: Xubuntu 13.04 "Raring Ringtail" - Release amd64 (20130423.1)
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/zsh
SourcePackage: xfce4-settings
UpgradeStatus: Upgraded to utopic on 2014-10-18 (0 days ago)

[Thaddaeus Tintenfisch (thad-fisch-deactivatedaccount)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please try to obtain a backtrace following the instructions at http://wiki.ubuntu.com/DebuggingProgramCrash and upload the backtrace (as an attachment) to the bug report. This will greatly help us in tracking down your problem.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.