Something suspicious to me, the GL context Mir is giving to Qt is missing the alpha channel:
Settings "QSG_INFO=1", you get: qt.scenegraph.info: texture atlas dimensions: 2048x2048 qt.scenegraph.info: R/G/B/A Buffers: 8 8 8 0 qt.scenegraph.info: Depth Buffer: 24 qt.scenegraph.info: Stencil Buffer: 8 qt.scenegraph.info: Samples: -1 qt.scenegraph.info: GL_VENDOR: Qualcomm qt.scenegraph.info: GL_RENDERER: Adreno (TM) 320 qt.scenegraph.info: GL_VERSION: OpenGL ES 3.0 V@53.0 AU@ (CL@) the A Buffer should be 8. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to unity8 in Ubuntu. https://bugs.launchpad.net/bugs/1502093 Title: unity8 crash on mako rc-proposed/ubuntu with latest unity8/mir/powerd Status in Canonical System Image: New Status in unity8 package in Ubuntu: Confirmed Bug description: mako rc-proposed/ubuntu 256 + distupgrade of all the packages in the ovrerlay PPA The shell doesn't come up and unity8 crashes in a loop. Logs attached. To manage notifications about this bug go to: https://bugs.launchpad.net/canonical-devices-system-image/+bug/1502093/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
