[regression] Mir demo servers don't start at all in release 0.13.1 (mir-platform-graphics-* never installed)

Yep, the issue is just that we're missing package `mir-platform-graphics-mesa2'

Is that an intentional omission to our dependencies?

Fix:
sudo apt-get install mir-platform-graphics-mesa2

It is intentional. C.f. -c 2295 and -c 2316. From the former commit message:

  Drop libmirclient8 dependency on client-platform drivers.

  Similar to libX11, which doesn't depend on an X11 server.

  This dependency is satisfied by other parts of the stack; the desktop-next and touch
  seeds.

This implies that the seed ought to be pulling in the drivers.

I don't have a wily install to hand but it sounds like mir-graphics-drivers-desktop is still pulling mir-platform-graphics-mesa1. (Which is what it does on vivid.)

There is no mir-graphics-drivers-desktop, because Desktop Next is not installed either. Just a fresh distro plus mir-demos.

This might be intentional but if it trips up myself and kgunn in the same day maybe we need more smarts, somewhere.

Assigning to RAOF as he has the background on this.

From bregma on IRC mir channel :
"our Unity8 desktop session no longer comes up in Wily unless we explicitly install some Mesa packages: it looks like the Mir package dependency chains have changed recently that means software in the Ubuntu archives are currently broken"

So. The ubuntu-desktop-next metapackage has a dependency on mir-graphics-drivers-desktop, which in turn has a dependency on mir-platform-graphics-mesa2.

So having the ubuntu-desktop-next metapackage installed should be sufficient to get you appropriate drivers.

We have a task for making the error message more useful to end-users on our backlog.

Adding a dependency on mir-graphics-drivers-desktop to unity8-desktop-session-mir is probably the best “solution”.

The next level of solution is fixing germinate so that we can pre-seed dependencies. Then we could add a mir-graphics-drivers-mesa | mir-graphics-drivers-android dependency on something and not pull in mesa on the phone. Even that's not really right; we're merely hoping that no one installing using apt will need the android drivers.

I'm adding the unity8-desktop-session package to this bug report since this is where RAOF says we need to add a dependency. This won't fix Daniel's use case in the bug description since he is just trying the mir_demo_server on a desktop.

At any rate, anyone using the unity8-desktop-session-mir package will have the correct packages installed once the "fix" goes in.

It's still a regression. "apt-get install mir-demos" does not work, when it used to work.

Although I understand the "Won't Fix" stance too. That's fine, but maybe we can think of some more creative or useful solution still. Like changing the error message you get when no drivers are present from the cryptic text it is to something simple and informative that allows the user to fix the problem themselves (see also bug 1381398).

This bug was fixed in the package unity8-desktop-session - 1.0.12+15.10.20150609-0ubuntu1

---------------
unity8-desktop-session (1.0.12+15.10.20150609-0ubuntu1) wily; urgency=medium

  [ Chris Townsend ]
  * Add a dependency for mir-graphics-drivers-desktop since the Mir
    packaging does not provide a way to pull this meta-package in.
    Without this package, the Unity 8 desktop session will not start.
    (LP: #1460868)
  * Create the wizard-has-run file if it doesn't exist when logging into
    Unity 8 to bypass the OOBE wizard on a desktop session. (LP:
    #1463065)

 -- CI Train Bot <email address hidden> Tue, 09 Jun 2015 14:17:17 +0000

Note this bug is about the Mir demo servers not starting. unity8-desktop-session has nothing to do with that so it should have been a separate bug really.

Hi Daniel,

I went back and forth in my mind on whether I should use a new bug for the unity8-desktop-session task. I decided to use this bug because 1) This was the bug pointed out by the Mir team when we inquired why mir-graphics-drivers-desktop was not getting installed and 2) It's really the same bug that affects us as well. Given that, I thought it would be OK to just use the same bug for our project as well. Sorry for any confusion I may have caused in this bug:)

It's fine. Just one of those cases where if you want the issue really truly fixed then you'll need Fix Released across all the bug tasks.