Subject: Re: Debugging a device driver (How to?)
To: None <>
From: Mirian Crzig Lennox <>
List: tech-kern
Date: 04/15/1999 10:50:41
Riaz Randeree <> writes:
> Hello
> I have tried serial debugging:
> I start debugging by booting the kernel with 
>         boot netbsd.dbg -d
> Then on the other machine, using 2nd serial port 
>         (gdb) set remotebaud 9600
>         (gdb) target remote /dev/tty01
> Nothing happens. What am I missing?

Grrrr.....  don't get me started.  I spent the better part of two days
banging my head against the wall trying to get this to work.  :(

The problem is due to a bug in NetBSD's com driver.  The fix,
including patch, is in PR #6502.  (The patch is against 1.3.2 but it
should still work on subsequent releases.)

I've seen a recent request for someone with commit access to
incorporate this fix into 1.4.  I'd like to take this opportunity to
emphatically echo this request.  It makes me rather sad to think how
many potential developers of drivers for NetBSD may have been
discouraged away from doing so by the fact that serial line kernel
debugging does not work at all unless one takes the time and effort to
track down this obscure bug.