One common criticism for this open source driver is with how Nvidia moves most of functionalities previously implemented in the driver into the (giant) firmware blob. The (thinner) driver is open sourced, but the giant firmware blob is basically a proprietary black box, so Nvidia can claim that their driver is open source while keeping their GPU as closed as before.

Not just Nvidia that’s doing this though. Qualcomm has been doing this for a long time on their ARM SoC.

Their userspace drivers are not open source yet (and probably will never be)