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Date:      Tue, 23 Apr 96 9:00:15 MDT
From:      Greg Lehey <lehey.pad@sni.de>
To:        smpatel@umiacs.umd.edu (Sujal Patel)
Cc:        current@freebsd.org, hackers@freebsd.org (FreeBSD hackers)
Subject:   Re: request for a new "feature" as regards DDB
Message-ID:  <199604230703.JAA07879@nixpbe.pdb.sni.de>
In-Reply-To: <Pine.NEB.3.92.960422180106.209p-100000@xi.dorm.umd.edu>; from "Sujal Patel" at Apr 22, 96 6:02 pm

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>
> On Mon, 22 Apr 1996, Marc G. Fournier wrote:
>
>> 	I happened to be off of vt0 when it died, with no way to
>> switch to vt0 and see what ddb was showing, and since I had to
>> cold boot the machine as a result, couldn't even get a core dump :(
>>
>> 	So...any way of having an auto-switch to vt0 if the system
>> crashes with DDB enabled?

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.

> What about making DDB a LKM also?  Whenever I find myself using DDB, I
> know that the system is going to panic, not everyone needs DDB loaded at
> all times (and rebuilding kernels is such a pain).

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

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

I'm copying hackers on this, since that is where we discussed ddb
before.

Greg



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