Unity 5.3.4 Linux Issues

After upgrading to 5.3.4 (both f1 and p1 as of the time of this post) I get crashes when starting the player on Linux. Happens with a vanilla unity project, so nothing special about my game. The crash happens almost immediately after start. If I run with -nographics as a command line option, the player will start (I can hear my game's main menu music playing).

The backtraces also show problems with graphics initialization. Each bt is slightly different for 5.3.4f1 and p1. I've included both in the spoiler below.

Spoiler

5.3.4f1
#8 0x00007f96859e7703 in std::terminate() ()
from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9 0x00007f96859e7922 in __cxa_throw ()
from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#10 0x00007f9685a391a7 in std::__throw_logic_error(char const*) ()
from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x00000000012243a7 in basic_string ()
#12 0x0000000001224b53 in gles::InitCaps ()
#13 0x0000000001219c8b in ApiGLES::Init ()
#14 0x000000000120ac51 in GfxDeviceGLES::Init ()
#15 0x00000000012184dc in CreateGLESGfxDevice ()
#16 0x0000000001197895 in GfxDeviceWorker::Startup ()
#17 0x0000000001195a23 in CreateClientGfxDevice ()
#18 0x0000000000751f7a in InitializeGfxDevice ()
#19 0x00000000008d0108 in InitializeEngineGraphics ()
#20 0x00000000008a922d in PlayerInitEngineGraphics ()
#21 0x0000000000489b9c in main ()


5.3.4p1
#4 <signal handler called>
#5 0x00000000011c0dc7 in ContextGLES::Acquire ()
#6 0x0000000001211f65 in ~GfxDeviceGLES ()
#7 0x000000000121e228 in CreateGLESGfxDevice ()
#8 0x000000000119d555 in GfxDeviceWorker::Startup ()
#9 0x000000000119b6e3 in CreateClientGfxDevice ()
#10 0x00000000007520aa in InitializeGfxDevice ()
#11 0x00000000008d0258 in InitializeEngineGraphics ()
#12 0x00000000008a935d in PlayerInitEngineGraphics ()
#13 0x00000000004899a6 in main ()

Note that everything was cool with Unity 5.2 and earlier versions. This problem popped up with Unity 5.3.4 (I can't say about 5.3 version earlier than 5.3.4, as 5.3.4 is the first 5.3.x I tested).

In the release notes for 5.3.4p1 I note this:

I bet this is related since the backtrace from f1 to p1 changed... but I still get a crash. I can also skirt this issue by running with -force-opengl on the command line. That lets my game start and run, but the main menu movie texture doesn't show in this case (guess that is another issue).

So, I wonder what changed in 5.3.4 to cause this crash and is it related to some new graphics requirements that cause some machines to crash (I have at least one beta tester that says things are fine on his linux box).

I've also logged a bug (783853).

[edit]
Ok, so this: http://blogs.unity3d.com/2015/05/26/dx11-features-on-mobile/ has also become the default rendering backend as of 5.3 on Linux. That explains the sudden change in behavior in 5.3. Doesn't help with the crash, but at least there's a hint as to why.

[edit2]
So looks like Unity now requires OpenGL 3.2 support... and my test machine is at 2.1. That explains why it doesn't work, but of course not the crash. If it weren't for the hard crash I bet there would have been a nice message (like p1 was supposed to fix) and the hours I've spent on this would have collapsed down to moments instead