libdrm's documentation is severely lacking, including several references to not-yet-written man pages (eg. #27).

One idea to fix this is to:

• convert the man page to inline documentation akin to what the kernel uses and generate the man pages from that
• add CI check that all exported functions have a man page (with a list of known undocumented functions), to make sure new functions get properly documented
• add documentation to all the exported functions and remove these functions from the list of undocumented functions