On Mon, Dec 18, 2000 at 10:46:00AM -0600, Phil Howard wrote:
> David Cantrell wrote:
>
> > If you knew how to send "Stop" through the serial terminal, all would be
> > good, right? Because SysRq on the SPARC is Alt+Stop+<letter>. I started
>
> "Stop" doesn't have an ASCII code. It would be a keyboard scan code. But
> there may be some escape sequence equivalent to it. There's probably a
> reason Sun chose to use BREAK to drop to PROM instead of some code for "Stop".
Damn. If Stop had an ASCII code, then that could mean the Props key has
an ASCII code and I could write something to trap the Props key. I was
thinking of having the machine say "map props" if you press it. :)
> > to make a patch in /usr/src/linux/drivers/char/sysrq.c, but ran across
> > this comment:
> >
> > /* Don't use 'A' as it's handled specially on the Sparc */
> >
> > Is it safe to trap A for SysRq functions on the SPARC? Might be better to
> > find a way to send Alt+Stop through the serial terminal. Idunno.
> > Suggestions?
>
> If they mapped "Stop" to SysRQ, it might be that "A" is different in that
> perhaps it causes an NMI or something. We'd need to get someone who knows
> Sparc hardware to explain what really happens. Charles?
Stop+Alt is SysRq, but I think Stop+A+<anything> causes a BREAK. Maybe, I
don't know. I'm making things up now. Charles!
> I'm all for having a setting to control the BREAK behaviour. That can be a
> boot parameter and/or a /proc entry. The /proc entry would make it easy to
> change on the fly.
If it can be explained and tested, I see no reason why it shouldn't be a
configuration step during the setup program. Something that writes out
/etc/break.conf or something like that (rc.S could read it in and set the
appropriate stuff).
--
David Cantrell | david@slackware.com *
KG6CII | Slackware Linux Project
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