🚀 go-pugleaf

I'm having great difficulty writing an asynchronous Unix style device driver
running under BSD/Mach/NeXTStep. Are there any asynchronous device driver
authors out there that could help me please?. There's zippo documentation on
how to do this in NeXT's "Writing Loadable Kernel Servers" manual, and it's
proving very difficult.

In particular, implementing select() for the driver is a nightmare; the
"selwakeup" kernel function is undocumented, and it's operation is different
to the same function on other BSDish systems, such as a Sun. The only example
code I can find is from the Sun device driver manual, and it appears to have a
race condition where the driver could get an interrupt between when the
driver's xxselect returns false and the kernel puts the process to sleep;
causing the process to hang since it's already missed the chance to selwakeup.

Egan and Teixeira's "Writing a UNIX Device Driver" doesn't even come close to
describing an asynchronous driver.

Is there any hope for me?.

Any help would be greatly appreciated,
Graham