Comment 15 for bug 1274779

It is unlikely to explain the cursor flicker - the hang here is quite rare. But a regular GPU hang could produce the symptoms you describe if the hang coincided with the cursor being hidden itself by software (the command to show the cursor will then need to wait for the hangcheck to be detected in some extreme case). Given that it requires a combination of unlikely situations, I doubt it actually explains the cursor flickering (and if it was a constant hang, the kernel will declare the hardware as wedged).