Caught exception at Mir/EGL driver boundary (in setSwapInterval) in clients and tests

[Kevin DuBois]

messages like this have started appearing in logs and test runs:

root@ubuntu-phablet:/home/phablet/mir/bin# LD_LIBRARY_PATH=../lib ./mir_demo_client_egltriangle.bin
Mir chose pixel format 1.
Using pixel format 2.
Current active output is 540x960 +0+0
[2017-01-25 08:38:53.915333] <ERROR> AndroidWindow: Caught exception at Mir/EGL driver boundary (in setSwapInterval): Dynamic exception type: St12system_error
std::exception::what: Operation not permitted

The don't appear to be causing test or client smoketest failures

[Kevin DuBois (kdub)]

seems this started happening in rev 3982, and the exception is coming while trying to wait for the swapinterval configuration with a waithandle.

[Kevin DuBois (kdub)]

The issue will have broken sync when setting swapinterval, as the function could return before the configuration has been applied server side. The swapinterval will end up in the correct state, but perhaps the loss of sync of swapinterval state could be a nuisance.

[Kevin DuBois (kdub)]

Oh, actually, ignore^, I don't think sync would be lost. The issue occurs when trying to set the swapinterval twice with the same value.

The side effect is that the driver would get an error RC for issuing the set_swapinterval hook (-1 on android, MIR_MESA_FALSE for mesa). I think most sensible drivers would ignore this error, but that relies on the drivers being sensible.