mir_demo_client_eglsquare soon freezes

[Alan Griffiths]

$ mir_demo_server --launch mir_demo_client_eglsquare

Move the cursor over the client:

expected: the square follows the cursor
actual .: the square follows briefly then freezes

This happened since the 0.26 series, but seems to predate updating the clients to use the RS APIs.

[Alan Griffiths (alan-griffiths)]

Running the 0.26 client against a 0.27 server exhibits the problem, so the rewrite of examples is probably not involved.

Further, the program is hanging in me::Context::swapbuffers() - the fourth time this is called.

[Alan Griffiths (alan-griffiths)]

Hmm, I see the problem with -r 4075 while earlier versions fail to build: Mesa egl needs mir_presentation_chain_set_mode() which was introduced in 4075.

[Alan Griffiths (alan-griffiths)]

OK, through the tedious process of merging into [a copy of lp:mir/ubuntu] and resolving conflicts I find that:

  o [a copy of lp:mir/ubuntu] + [-r 4033 lp:mir] works; and,
  o [a copy of lp:mir/ubuntu] + [-r 4034 lp:mir] is broken

revno: 4034 [merge]
author: Andreas Pokorny <email address hidden>
committer: Tarmac
branch nick: development-branch
timestamp: Wed 2017-02-15 22:38:46 +0000
message:
  mirserver: Use the normal mir connection to send input to clients

  Input Events are now sent through the connection and contain a window id to refer to the destination window. So all types of events occur on the client side in the order they were sent from the server. Additionally the conversion between android::InputMessage and MirEvent is avoided. This simplifies adding new event types or extending the content of existing input events. The client code needed only minor changes to not filter out MirInputEvent.
  .

  Approved by Brandon Schaefer, Kevin DuBois, mir-ci-bot.

And that's EOW

[Alan Griffiths (alan-griffiths)]

OK, so this looks like eglsquare depending on undefined behavior - it tries to paint in the window event callback. That "worked" for input events prior to -r 4034.

[Mir CI Bot (mir-ci-bot)]

Fix committed into lp:mir at revision None, scheduled for release in mir, milestone 0.27.0