Date: Tue, 24 Feb 1998 19:11:48 +0900 From: Kazutaka YOKOTA <yokota@zodiac.mech.utsunomiya-u.ac.jp> To: Andrzej Bialecki <abial@nask.pl> Cc: freebsd-current@FreeBSD.ORG, yokota@zodiac.mech.utsunomiya-u.ac.jp Subject: Re: Proposed addition to panic() behaviour Message-ID: <199802241011.TAA12153@zodiac.mech.utsunomiya-u.ac.jp> In-Reply-To: Your message of "Tue, 24 Feb 1998 10:58:56 %2B0100." <Pine.NEB.3.95.980224105141.18610C-100000@korin.warman.org.pl> References: <Pine.NEB.3.95.980224105141.18610C-100000@korin.warman.org.pl>
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>> > 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). > >I see. But syscons driver _knows_ how to switch from X to text mode, >doesn't it? No, it doesn't. >Even if it *sometimes* fails (because some obscure registers >are garbled), *most of the time* it produces useful result. This would be >enough... > >Hmm... Or is it the X server who knows how to do it, not the syscons? Yes. This is the case. >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. Kazu To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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