Most drivers are shunted to the User side of the fence these days,
with the notable exception of video card drivers, which need
bare-knuckle Kernel mode performance. But even that is changing; in
Windows Vista, video drivers are segmented into User and Kernel
sections. Perhaps that’s why gamers complain that Vista performs about
10 percent slower in games.
A good guess might be that the “real” driver is running in kernel mode, while DRM shenanigans tied to the driver are taking place in user mode.