[vtkusers] Many VTK build tests fail when run from Jenkins/Bamboo or VNC display, even when DISPLAY is set to good opengl-enabled display

[John]

Ben, thanks muchly.

MESA_GL_VERSION_OVERRIDE=3.2 made a huge difference to running the tests
on vnc.

With the override set, I'm able to run tests on vnc with only 102
failures, and most of those failures are from the TestGPURayCast group.
So there's obviously something about that group which doesn't like the
VNC/Mesa, but almost everything else is good.

The above success with VNC was enough to motivate me to have another
look at the main issue I've been having when running tests on nvidia.

And thus began another trip down the rabbit-hole and almost to the brink
of losing my sanity. I did find the answer though. After countless tests
& hours of grief & frustation, I have solved it.

The problem, as it turns out, was two things:

1) I have screensaver/power management disabled in xfce4, but DPMS was
still being enabled by Xorg. When DPMS kicks in and turns off the
display, suddenly tests start to fail. 347 out of 1314 will fail if DPMS
has had the monitor turned off for the whole testing run, and, to make
things more confusing, if the DPMS kicks in halfway through a test run,
the number that fails will be lower.

So I am now enabling xfce-power-manager and ensuring it is set to
DISABLE screen blanking and DPMS, and I'm also using "xset s off -dpms"
which should accomplish the same, if xfce-power-manager isn't running.

2) I typically have two X displays running on my nvidia card, and switch
between them using ctrl-alt-Fx. If I try to run tests on the X display
which is not selected, again, 347 of the tests fail.


So, when I have DPMS disabled, and the right X display selected with
Ctrl-Alt-Fx, I am now getting 100% success on all tests, on my mvidia card.

100% success. 100% confirmed.

I do find this situation incredibly frustrating and utterly depressing
though. Once again, I wonder why I ever began to use Linux. What sort of
utter garbage is this, when having a monitor turn off due to DPMS
suddenly breaks applications?!?!

I just don't understand it. This doesn't happen on Windows. Imagine if
Word or Autocad or Google Chrome or Call of Duty would suddenly crash
every time you had a cup of coffee & your monitor went into power-saving
mode.

And what sort of nonsense is going on, when switching to a 2nd X display
breaks apps on the first.

I used to have Quake3 running on one X display and my normal desktop on
another X display, 15 years ago. But Quake3 never crashed with OpenGL
errors when I used Ctrl-Alt-Fx to switch back to my regular desktop.
Perhaps the whole X display and every app on it used to be suspended
when i switched VTs, but I don't think that was the case. I'm pretty
sure I used to be able to hear the audio continuing, so quake3 & the x
server must've still been running, even when the vt was not selected.

It's all just utterly ridiculous. It shouldn't happen. But apparently
this is the state of Linux/Xorg/nvidia now, in 2018. Just appalling.


On 2017-12-28 12:16 AM, Ben Boeckel wrote:
> On Sat, Dec 23, 2017 at 04:57:00 +1030, John wrote:
>> ps Re using VNC, for me it was an almost total failure, so i quickly
>> gave up and switched to sending the tests to my main Xorg/nvidia head.
>>
>> Under vnc,the tests fail with an error message which says:
> 
> What if you set `MESA_GL_VERSION_OVERRIDE=3.2` in the environment?
> Something causes a request of a compat profile when on VNC. This tells
> Mesa to claim it has a compat profile at 3.2 (this profile is
> technically missing old functions, but VTK doesn't need them anyways).
> 
>>     Preferred profile: compat (0x2)
> 
> You can see that a compat profile was requested here.
> 
> --Ben
>