Crash (freezing) of panel in Linux

[bprcek]

Hi all

I encountered a problem wit either frozen, or crashed panel after a resolution of screen has been changed.
I have installation of WinCC OA 3.15 (Patch 12) running on OS Linux 3.13.0-77.

First of all I checked panels of our project. But afterwards I created simple project with one panel and one button inside.
I run this panel in Quick test module.
I changed resolution of screen one level up. So far so good. Button react on click with mouse.
I changed resolution of screen back to the previous resolution. After I confirmed change of resolution I click on button in panel.
And now usually I get two different results .
Either WinCC OA disappears (I mean crash of panel and WinCC OA console), or panel is frozen.

For explanation. Originally this problem has been found during remote connection to the pc where project is running.
If someone has higher resolution on own pc as it is on project pc then this strange behaviour happens.
Could someone help me to fix this problem ?
Thanks for help

Brano

[emaddocks]

Hi all,

We are also experiencing this issue on our Linux platform (RHEL GNOME v 3.14.2) when we turn monitors off. If the primary monitor is turned off the primary vision will move to the second monitor and be hidden behind the second vision. The second vision continues to operate but when we switch to the primary vision and click on it anywhere it crashes/disappears as well as the second vision!

Did you find a resolution to this issue Brano?

Any help would be much appreciated. Our WinCC OA version is 3.15 (Patch 13).

Regards
Eric

[emaddocks]

When the vision crashes the following entry is observed in the UI log:

QPaintDevice::metrics: Device has no metric information
Unrecognised metric 3!


It seems this is a Qt5.5 issue as described in the following link…

https://bugreports.qt.io/browse/QTBUG-4 ... owAll=true

Is it possible to run WinCC OA with a newer/different Qt version?

[leoknipp]

You cannot do an upgrade of the QT version on your own for WinCC OA.
The used QT version is defined by WinCC OA as we are compiling/building WinCC OA with a specific QT version.

Possibly you can do an upgrade to WinCC OA 3.16. 3.16 uses QT 5.9.2.

Best Regards
Leopold Knipp
Senior Support Specialist

[emaddocks]

Hi Leopold,

This is occuring on a production system so just upgrading to 3.16 without knowing if the issue will be resolved is not an option.

Are you aware of this issue in version 3.15? If so, could you please confirm that it has been fixed in version 3.16?

Regards
Eric

[leoknipp]

I searched in our database if the error you have written occurred in any of our systems and if it was reported to our development department.
In the database I could not find any information.
If QT states that it is solved in newer QT versions it should also be fixed in WinCC OA 3.16.
Possibly you can do the test on your own in a test system using WinCC OA 3.16.

Best Regards
Leopold Knipp
Senior Support Specialist

[emaddocks]

Hi Leopold,

This does not only occur on our project but the demo project that comes with v3.15. Could you please attempt to reproduce the issue at your end and verify if it is actually an issue with the underlying platform?

In reproducing the issue please make sure to use a workstation that uses display connections that issue hot plug signals when the monitor is turned off and on. We are using Display Port connections but I believe HMDI and DVI will also issue these signals. It seems that these hot plug signals trigger a screen configuration change on Linux and this configuration change triggers a script in the Qt library (that contains a bug) to execute to refresh the vision. At this point the vision crashes.

Regards
Eric

[emaddocks]

Hi Leopold,

We have raised this issue on the bug tracker (ID 6542 - Vision crash on screen refresh).
Could you please pass on any findings you may have made to Alexander Gorbatykh.

Regards
Eric

[emaddocks]

The bug has been identified in v3.15 up to Patch 20. Developers are working on a fix.

If you can, upgrade to v3.16 Patch 11 as this version apparently does not have this issue.