I'm still fighting with Qt and I managed to get an "SGX Out of mem event" on Nokia N900. It happens when I load some .obj models in my QGraphicsScene (usually after the fourth-fifth). Any idea on what is causing it or how I could trace it?
My guess is that you are running out of graphics memory (the N900's GPU is an Imagination Technologies PowerVR SGX 530).
As far as I can see, the N900 does not have any EGL extensions for directly querying graphics memory usage. In this case, the best you can do may be to reduce graphics memory usage by limiting the complexity of the scene you are trying to render - in other words, load fewer OBJ models, or reduce the complexity (number of polygons) of individual models.