I struggled with vendor drivers for chipsets for years (yes this company too). They are generally awful. Most are warmed-over demo drivers from the original silicon vendor, intended to exercise chip features but no diligence to adhere to specs, protocols, handle (any) error conditions, be readable or supportable.

Vendor "support" for their driver means a third-string intern/student who hashes together patches that reveal profound ignorance of the architecture.

Its not just NIH; the chain of custody from silicon designer to you just doesn't include ANYBODY who has your interests/your customer's interests in mind. They are more concerned with making the driver portable across their product line, doing it cheaply, getting it to market at the same time their hardware releases etc.

Any robustness/architecture/responsible software processes have to be your business and yours alone. This probably means rewriting the whole driver, using the demo driver for reference but ONLY for chip-specific info.