Date: Tue, 24 Feb 1998 11:13:16 +0100 (CET) From: Andrzej Bialecki <abial@nask.pl> To: Kazutaka YOKOTA <yokota@zodiac.mech.utsunomiya-u.ac.jp> Cc: freebsd-current@FreeBSD.ORG Subject: Re: Proposed addition to panic() behaviour Message-ID: <Pine.NEB.3.95.980224111015.22979A-100000@korin.warman.org.pl> In-Reply-To: <199802241011.TAA12153@zodiac.mech.utsunomiya-u.ac.jp>
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On Tue, 24 Feb 1998, Kazutaka YOKOTA wrote:
> >> > Many people (including me) suffered from panic while their console was in
> >> > graphic mode (e.g. X Window). I don't know if this would be proper place
> >> > to do this, but in case of panic (where everything is lost anyway) just
> >> > add there the code to forcefully reset the video card to set it in
> >> > known (and useful) mode...
> >>
> >> See the numerous "DDX in the kernel" discussions in the -current list
> >> archives to see why "just add there the code to forcefully reset the
> >> video card" requires knowing how the video card got in the mode it's
> >> in, and specific knowledge of the card (hint: write-only hardware
> >> registers not shadoewed in RAM).
> >
> >But I also vaguely recall something like dump of VGA registers
> >when booted with -v, so they are stored somewhere, right?
>
> The video BIOS ROM contains the table of STANDARD register values only.
> We cannot know which additional registers should be set to what value.
Ok. Call me stubborn, but why can't we just write the STANDARD register
values corresponding to the initial state of the card, and if the screen
is still garbled, well <shrug> - at least we tried... But, my point is (or
maybe I'm still wrong), that *most of the time* this will restore the card
to some usable state...
Andrzej Bialecki
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abial@warman.org.pl | if(halt_per_mth > 0) { fetch("http://www.freebsd.org") }
Research & Academic | "Be open-minded, but don't let your brains to fall out."
Network in Poland | All of the above (and more) is just my personal opinion.
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