frameCounter

[Fritz, Jannik]

Hello,

I'm trying to write a frame-grabber software for my display which is using the wayland-ivi-extension (https://github.com/GENIVI/wayland-ivi-extension). The frame-grabber software is used for a test-automation to check if the display render the pictures correctly.
I always want to take a screenshot, if something changed on my surface. Actually, my problem is to detect changes on my surface.
After I looked up in the ivi-layermanagement-api I have noticed that a surface has particular properties ("ilmSurfaceProperties"). One of these is the property "frameCounter", which shows the already rendered frames of a surface. So if the Counter increases by one, something changed on the surface.
One idea was to use the function "ilm_surfaceAddNotification" to get a callback if the property "frameCounter" changed. However, the callback function was not invoked, after my display rendered. It looks like the property is not observed for notification.
Is there an elegant way to detect changes on my surface by callback without polling the property by myself? Maybe some kernel-events or other API callbacks.
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