Yes, the XS has internal test patterns. I still use the AVS disk to check the source components. None of my source components need tweaking though.

With a VP that has complete Grey Scale, Gamma, and 3-D CMS, you leave the display as neutral as possible and make all calibrations with the VP. If you use the display, you'll be chasing your tail all day long. I just use the display to set grey scale gain to make sure I have enough room to move it with the XS.