> Basically, video memory could be gone after Suspend/Resume, VT-Switch and so on.

This actually makes sense: for example, a new task has swapped out previous task's data, or host and guest are sharing the GPU and pushing each others data away. I don't understand why this is not a part of GPU-related standards.

As for solution, discarding all the GPU data after resume won't help? Or keeping the data in the system RAM.