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What Brandon Schaefer talks about

Brandon Schaefer

When Choosing a Backend Fails

There was a recent GDK release into zesty that now probes for Mir over X11. This can cause issues when still using an X11 desktop such as Unity7 when a Mir server is running at the same time.

A common way to test Mir is to run it on top of X, which is called Mir-on-X. This means there are now two display servers running at the same time.

An example of an issue this can cause is gnome-terminal-server. It will attempt to spawn its clients on Mir instead of X11 once the Mir server is opened. You now attempt to spawn a new terminal which causes the gnome-terminal-server to crash since it now tries to spawn on Mir but you already spawned terminals on X. As you can imagine this is frustrating to your workflow!

A simple workaround is to add this to your ~/.profile:

if [ "$XDG_CURRENT_DESKTOP" = "Unity:Unity7" ]; then
    dbus-update-activation-environment --systemd GDK_BACKEND=x11

Depending on your desktop the “Unity:Unity7” bit will change.

As more toolkits will start to pick other display servers as their first pick more of these issues will become possible. Other environment variables to consider:


A bit more detail on the issue can be found here:

Choosing a Backend

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Brandon Schaefer

Mir windowing system in Kodi

Here is a video of Kodi running on mir [1]. The source for the port is sitting [2 xbmc/xbmc/windowing/mir ]. My plan is to upstream the changes and maintain the port [6]. There are some more things to fix up, but the main part is ready to upstream.

It will be compile time support, meaning you’ll need to compile with mir support specifically. As Kodi does not support runtime windowing selection. This also means it’ll have a low risk to the main code base. The port supports both opengl and opengles. I also need to test this out on an embedded device (such as raspi/dragon board). Ideally creating a nice kiosk Kodi media center would be awesome running on mir!

I have also snapped up Kodi with mir support [3] with help from [4] and Alberto Aguirre [5]. This is an amazing use case of a snap, having Kodi in a kiosk type system. The main goal as well is to get this working on an embedded device so you install a ubuntu core image, then just install this snap through the store and you’ve a fully working media center!

If you’ve any questions feel free to poke me (bschaefer) in freenode #ubuntu-mir anytime or email me at

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Brandon Schaefer

Hello world!

Welcome to Canonical Voices. This is your first post. Edit or delete it, then start blogging!

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