I don't know anything about nvidia but internet says 173 and 96xx are not compatible with x11-server 1.11
Compatibility with 1.10 was added in the latest version, in August last year, 6 months after 1.10 was released, and a week before 1.11 was released. It has now been more than 6 months since 1.11 was released, 1.12 was released last month, so should we still expect 1.11 (and recent kernels) support to happen?