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Date: Tue, 23 Apr 1996 19:28:35 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199604230928.TAA12645@godzilla.zeta.org.au>
To: lehey.pad@sni.de, smpatel@umiacs.UMD.EDU
Subject: Re: request for a new "feature" as regards DDB
Cc: current@freebsd.org, hackers@freebsd.org
Sender: owner-hackers@freebsd.org
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>>> 	So...any way of having an auto-switch to vt0 if the system
>>> crashes with DDB enabled?

Use syscons.

>Good idea.  I'll add it to my list.  For those who don't know, I had
>planned to make some major changes to ddb Real Soon Now.

>> While we're talking about DDB, can't we have it timeout in 30s if you
>> don't hit a key (and then generate a core dump).

>Also a good idea.

Bad idea.  You should make sure that ddb is never entered if you're not
around to watch it.

>> What about making DDB a LKM also?  Whenever I find myself using DDB, I

>Yes, I had planned on that.  Who can give me info on how to write
>LKMs?

Begin with /usr/src/share/examples/lkm.

>On the other subject, changing out of X into character mode: I believe
>that a debugger should have as little involvement with the subject
>being debugged (in this case, the kernel), as possible.  I can't see

Yes, it shouldn't touch anything that it doesn't fully understand or
can't restore.

>why ddb shouldn't understand enough about generic VGA to be able to
>put it back in 25x80 mode.  Somewhere I have a little program which I
>used to do this under BSD/386 0.3, where the X server wasn't always
>successful.  It's only a few lines.  I'm sure somebody's going to come
>up with "yes, but that's not completely generic", but I don't think
>this is an adequate argument.  Make it a config option for ddb, and

"yes, but that's not completely generic" :-).

>it'll handle 98% of all hardware.  If somebody with the other 2%
>wants, they can do it for that hardware as well.

It'll only handle 98% of all hardware that is running in a VGA compatible
mode.  I guess most X modes aren't VGA compatible.

Bruce