Subject: How to probe for a QBus device?
To: None <>
From: Jochen Kunz <>
List: tech-kern
Date: 01/25/2002 20:25:49

I am on the way writing rf(4), a driver for the RX01/02 8" Floppy drive
that can be found on VAXen. I have now the needed knowledge about
autoconf(9) to write rf{,c}_{match,attach}, but I am not shure how to 
do the detection of the controller on the QBus. I looked at other QBus
drivers and there are comments like:
 * Force the controller to interrupt.

I know that that was the way in 4.xBSD. According to driver(9) NetBSD
runs autoconf(9) when interrupts are disabled. So I designed a rfc_match

that does not generate an interrupt. 
Now I get from sys/dev/qbus/uba.c:ubasearch()
rfc0 at uba0 csr 177170 didn't interrupt
I had a look at this fuction and it seams that it needs to get an
from the child device to catch the interrupt vector. Is that correct?
Is there anything unobvious else to observe when writing QBus drivers?

BTW: To save the time of other kernel hacker newbies I am writing a 
documentation about what I am doing and the knowledge that is needed. 
Chapter 1 "Das \texttt{autoconf(9)} System" is already finished... 
Yes. It is written in "Altdeutsch" (not "Neudeutsch" i.e. English) 
using LaTeX.