Ken,
  I am following the same path as you with my display driver. I think
I finally got the driver under control. I can do open, reset, switch
modes. I do not see any more problems with all other calls, I will
implement then as soon as I find time. Yes, I implemented those system
calls (traps) and also some of the slot manager. I had also to map in
0xF900000 space , as the driver uses hard-wired adresses like
0xF920000. I did not mess around SIntInstall and SIntRemove, I used
stub routines. I guess you did not come yet to control calls, but they
have the following problem: if I call them asynchronously, they jump
to the address specified in 0x8FC, which is zero. What is it, queue
handler? Anyway, there is no sign of thge true interrupt handler, so
this part of the code should be left alone (I guess).

Changed files: (yes, I had to add the assembler stubs for the driver
adn put some definitions into driver.h)
arch/mac68k/dev/grf.c
arch/mac68k/dev/grf_mv.c
arch/mac68k/dev/grfvar.h
arch/mac68k/dev/driver.h
arch/mac68k/dev/drv_dispatch.s
arch/mac68k/dev/nubus.c
arch/mac68k/dev/nubus.h
arch/mac68k/include/grfioctl.h
arch/mac68k/conf/files.mac68k
arch/mac68k/mac68k/macrom.c
arch/mac68k/compile/TARAS/Makefile



I had to define also a bunch of ioctl's for the driver functions (all
of them that are in the documentation and few more). If the numbers
I have chosen doees not look good to you, you are free to define
another set. Anyway, this calling interface is at high level of the
code, it can be refined later.


  I can send you the code, if you would like to look at it. It is big
and ungly, with printf statement all over the place, I am trying to
clean it.

	Taras.