[regression] Windowed clients of nested servers are all black

Bisected (on lp:mir). The failure started in:

------------------------------------------------------------
revno: 4000 [merge]
author: Kevin DuBois <email address hidden>
committer: Tarmac
branch nick: development-branch
timestamp: Mon 2017-01-30 06:37:42 +0000
message:
  mirbuffer: remove MirBufferUsage from buffer allocation. mir_connection_alloca
te_buffer will allocate the formerly-called "software buffer", and there are pla
tform-specific extensions for android and mesa, which allocate the formerly-call
ed 'hardware buffers'.

  Approved by mir-ci-bot, Chris Halse Rogers, Cemil Azizoglu, Alan Griffiths.
------------------------------------------------------------

Invalid for Ubuntu (because the regression has not yet made it into the wild)

pixel format was not communicated properly all the way back to the client buffers. This resulted in the nested server's EGLClientBuffer image import failing, only in the mesa platform.

Fix committed to lp:mir/0.26 at revision 4011, scheduled for release in Mir 0.26.1

Fix committed into lp:mir at revision None, scheduled for release in mir, milestone 1.0.0

This bug was fixed in the package mir - 0.26.1+17.04.20170209.1-0ubuntu1

---------------
mir (0.26.1+17.04.20170209.1-0ubuntu1) zesty; urgency=medium

  * New upstream release 0.26.1 (https://launchpad.net/mir/+milestone/0.26.1)
    - ABI summary:
      . mirclient ABI unchanged at 9
      . mirserver ABI unchanged at 43
      . mircommon ABI unchanged at 7
      . mirplatform ABI bumped to 15
      . mirprotobuf ABI unchanged at 3
      . mirplatformgraphics ABI bumped to 12
      . mirclientplatform ABI unchanged at 5
      . mirinputplatform ABI unchanged at 6
      . mircore ABI unchanged at 1
    - Enhancements:
      . Support for MirBuffer API that allows for better management of
        hardware/software buffers.
      . Support for MirPresentationChain API that allows better control
        over {de}queueing of individual buffers {from}to the server.
      . Interim support for MirRenderSurface API that provides a unit of
        renderable for lower level content such as MirBufferStreams and
        MirPresentationChains, etc.. MirRenderSurface API is marked
        deprecated as it (and the relevant entry points) will be renamed to
        MirSurface before general availability. It will initially be used for
        revamping support for EGL drivers.
      . Synchronous version of mir_prompt_session_new_fds_for_prompt_providers()
        API (mir_prompt_session_new_fds_for_prompt_providers_sync()) added for
        convenience.
      . Better name for MirPersistentId-->MirWindowId. MirPersistentId has now
        been deprecated.
    - Bugs fixed:
      . [regression] Unity8 stutters constantly (like half frame rate).
        (LP: #1661128)
      . mir 0.26 - spinner loading animation, minimize, maximize too fast.
        (LP: #1661072)
      . [regression] Nested server segfaults or rapidly logs exceptions when a
        fullscreen client starts [in mir_presentation_chain_set_dropping_mode
        ... std::exception::what: Operation not permitted] (LP: #1661508)
      . mir_window_request_persistent_id_sync seg faults when called twice.
        (LP: #1661704)
      . [regression] Windowed clients of nested servers are all black.
        (LP: #1661521)
      . Mir graphics platform ABI broke in series 0.26 but sonames never
        changed (LP: #1662455)
      . Fixes for 0.26 changelog.
      . [regression] mirscreencast hangs during screencast creation. (LP: #1662997)
      . libmirclient-dev missing build dependency on libmircore-dev. (LP: #1662942)
      . mir_window_spec_set_cursor_name() doesn't trigger
        mir::scene::SurfaceObserver::cursor_image_set_to. (LP: #1663197)
      . [regression] Software clients of nested servers are all black in Mir 0.25.0
        and later. (LP: #1663062)

 -- Cemil Azizoglu <email address hidden> Thu, 09 Feb 2017 21:46:32 +0000