Unfortunately it is not that well-defined. This is mainly a race condition between loading DRM modules (such as nvidia) and gdm starting up. So this should mainly be tested by people who are affected by this bug, i. e. they do not get X start up, or with only the framebuffer driver (meaning no 3D acceleration, poor video playback, and presumably also problems on user switching).
Unfortunately it is not that well-defined. This is mainly a race condition between loading DRM modules (such as nvidia) and gdm starting up. So this should mainly be tested by people who are affected by this bug, i. e. they do not get X start up, or with only the framebuffer driver (meaning no 3D acceleration, poor video playback, and presumably also problems on user switching).