ESIX device drivers

Dave Shepperd shepperd at dms.UUCP
Fri Mar 16 15:35:10 AEST 1990


Well, we got ESIX/rev C. Naturally, I wanted to put in my device
driver that works just fine on SCO Xenix and SCO Unix (and even sort
of ok on Ix) and naturally it didn't work. ESIX tech support was
no help. Anybody have a clue?

Symptom:
System reports ESIX booting... (or something like that) as
normal and the console screen blanks as normal but nothing more is
forthcoming. Dead, dead dead... 

Some facts:
My driver init routine is being called which initialises some local
variables in the driver proper. The problem persists even if I reduce the
init down to setting just ANY ONE variable and exiting, however, the init
routine completes successfully and the system boots if it changes none of
the local variables. These variables are declared in the Driver.c code not
in the Space.c code (there is no Space.c code). This driver is currently
being used in SCO Xenix, SCO/Unix and Interactive Systems Unix without this
problem (although, on Ix, it has a different problem).

What the hell?:
If I change the driver so it does the init the first time a process
uses it instead of at boot time, it works just fine (BTW: This is an
acceptable work around, however, it is not an optimum solution).

Guess:
The kernel memory that contains the driver code has not been set to
R/W (ie perhaps read-only) so any updates to kernel space result in
a protection violation but the boot process hasn't gotten around to
setting up a handler for such an event and it weeds out. Ok, I admit
this is not too plausible, so never mind.

-- 
Dave Shepperd.	    shepperd at dms.UUCP or motcsd!dms!shepperd
Atari Games Corporation, 675 Sycamore Drive, Milpitas CA 95035.
Nobody knows what I'm saying. I don't even know what I'm saying.



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