Dell Sputnik Tip: Mouse / Cursor is broken or frozen after resuming from suspend or sleep

For some reason my third generation Dell Sputnik (aka Dell XPS13 with Ubuntu pre-installed) sometimes has a frozen or broken mouse / cursor after I suspend or sleep my laptop.  You can easily get it working again (this is not a permanent fix) by switching to a different TTY and then back to the TTY that holds the x-server GUI.

  • ctrl+alt+F6 to switch to TTY6 (this will give you a terminal)
  • Do nothing in the terminal
  • ctrl-alt+F7 to switch back to the TTY7 which is the Ubuntu x-server
  • Voila… your mouse should be working again.

If anyone has a permanent fix, please let me know.

Installing Cython – x86_64-linux-gnu-gcc: error: unrecognized command line option ‘-fstack-protector-strong’

I went around and around trying to get Cython install on my Ubuntu 14.04 LTS box.  I kept getting:

x86_64-linux-gnu-gcc: error: unrecognized command line option ‘-fstack-protector-strong’

Turns out that the ‘-fstack-protector-strong’ option was not added to the GCC compiler until version 4.9.  Upgraded my GCC to the latest available fixed the issue.

The City of Munich — Switching Back to Windows from Linux?

 Munich’s much vaunted migration to Linux could be about to unravel, sending the city back into the fee-driven bosom of Microsoft.

The City of Munich, Germany has been a Linux user for over 10 years but it appears that city employees are clamoring to switch back to Windows.

The issue I see is that they built their own distribution – LiMux. It was originally based on Debian and then switched to Ubuntu. The last stable release of LiMux was in 2011 and is based on Ubuntu 10.04 LTS which was released in April 2010. That version of Ubuntu is seriously old in the tooth now — even Microsoft releases new version of Windoze faster.

Seems to me that the City of Munich suffers from “Not invented here” syndrome and would be better off if they just switch to an vendor with commercial support like Ubuntu or Red Hat instead of trying to build and maintain their own distro.

Uninstall all Python packages via pip

This is for my future reference because it’s really handy if you don’t want to drop a virtualenv or doing some crazy work on a vagrant box.  Even ignores any packages you installed from git or vcs sources with the -e flag

pip freeze | grep -v "^-e" | xargs pip uninstall -y

Logitech Unifying Receiver Pairing on Linux

This post is mostly for my future reference. Really simple to pair a new mouse with an existing receiver on Linux.

ltunify is a program resulting from the gathered knowledge on the Logitech HID++ protocol. It allows you to pair additional devices like keyboards and mice to your Unifying receiver, unpair existing devices and list information about connected devices. This section will show you how to install the ltunify program.

Besides a C compiler and a way to fetch sources (wget+tar or git), you will need Linux 3.2 or newer with the hid-logitech-dj module. On Debian and Ubuntu distributions, the required packages can be installed using:

sudo apt-get install git gcc

Fetch the sources and install ltunify to $HOME/bin/ using the next commands:

git clone
cd ltunify
make install-home

The following steps will assume that $HOME/bin is available in your path. If not, run:

export PATH="$HOME/bin:$PATH"

If everything went well, you should be able to run ltunify --help to show the available options:

Usage: ltunify [options] cmd [cmd options]
Logitech Unifying tool version dev
Copyright (C) 2013 Peter Wu <>

Generic options:
  -d, --device path Bypass detection, specify custom hidraw device.
  -D                Print debugging information
  -h, --help        Show this help message

  list            - show all paired devices
  pair [timeout]  - Try to pair within "timeout" seconds (1 to 255,
                    default 0 which is an alias for 30s)
  unpair idx      - Unpair device
  info idx        - Show more detailed information for a device
  receiver-info   - Show information about the receiver
In the above lines, "idx" refers to the device number shown in the
 first column of the list command (between 1 and 6). Alternatively, you
 can use the following names (case-insensitive):
 Keyboard Mouse Numpad Presenter Trackball Touchpad

The below session shows you how to use a device index to unpair a mouse.

$ sudo ltunify list
Devices count: 1
Connected devices:
idx=1   Mouse   M525

$ sudo ltunify unpair 1
Device 0x01 Mouse successfully unpaired

$ sudo ltunify list
Devices count: 0
Connected devices:

$ sudo ltunify pair
Please turn your wireless device off and on to start pairing.
Found new device, id=0x01 Mouse

$ sudo ltunify list
Devices count: 1
Connected devices:
idx=1   Mouse   M525

It is also possible to select a device by device type (case-insensitive). When multiple devices of the same type are available, the first one will be selected.

$ sudo ltunify unpair mouse
Device 0x01 Mouse successfully unpaired