Window with OpenGL Surface Is Not Refreshed After Sleep

[Jacek_T_]

Hi all,

I have an issue on Intel GPU that causes Windows application window not being refreshed after waking from sleep. The application is built on Qt framework, but issue does not occur on cards from different vendors, so I suspect a driver bug. Details:
CPU SKU: i7 6700K
GPU SKU: HD530
Graphics Driver Version: 23.20.16.4901
Operating System: Windows 10 64-bit
OS Version: 1607 build 14393.2007
Occurs on non-Intel GPUs?: Does not occur on NVIDIA GeForce GTX 1070 nor AMD Radeon Vega 64

Steps to Reproduce:
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1. Download attached application sources.
2. Build against Qt 5.8 or 5.10 (tested versions; easiest to do it in Qt Creator by opening .pro file).
3. Run application and observe colour of the bottom widget is changing.
4. Put system to sleep.
5. Wake up and observe colours are not changing any more. Also the menus are not highlighted when hovered (though work when clicked).

Expected Results:
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After sleep colour of the main widget should still be changing and menus should highlight when hovered.

Actual Results:
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Colour of the main widget is not changing after waking from sleep, menus are not highlighted on hover.

Additional Information:
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Application is programmed so it renders (in this simple case just clears) OpenGL surface just after every time back and front buffers of rendering surface are swapped.