From owner-freebsd-current Tue Jun 4 09:57:37 1996 Return-Path: owner-current Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id JAA25480 for current-outgoing; Tue, 4 Jun 1996 09:57:37 -0700 (PDT) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id JAA25472 for ; Tue, 4 Jun 1996 09:57:34 -0700 (PDT) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id JAA27039; Tue, 4 Jun 1996 09:50:21 -0700 From: Terry Lambert Message-Id: <199606041650.JAA27039@phaeton.artisoft.com> Subject: Re: Vm fixes NG To: james@miller.cs.uwm.edu (Jim Lowe) Date: Tue, 4 Jun 1996 09:50:21 -0700 (MST) Cc: fcurrent@jraynard.demon.co.uk, grog@lemis.de, FreeBSD-current@FreeBSD.ORG In-Reply-To: <199606041314.IAA08738@miller.cs.uwm.edu> from "Jim Lowe" at Jun 4, 96 08:14:06 am X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-current@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > > > On a related note, is there any way to stop X grabbing the Ctl-Alt > > > sequence and drop into DDB? > > > > We discussed this a while back while talking about ddb. The problem > > is that it's almost impossible to find a way to set the display card > > back to text mode. > > Syscons seems to be able to do this just fine via . It > would sure be nice to be able to drop into the debugger when running X > w/o having to switch to another virtual console first. Syscons intercepts the key sequence and sends a message to the X server saying "restore the console to the default mode". Then the X server runs and restores the console. Then the X server sends a message to syscons saying "OK, I've restored the console". Then syscons swaps screen memory with virtual screen memory on another virtual console. Obviously, if you have invoked ddb as a result of a panic, the X server isn't going to be responding to any "restore the console to the default mode" requests, since it isn't running on a panic'ed system. The only fix would be for *all* graphic modes to be settable *only* through the console driver, so that the console driver can unset them without having to ask a user space program to do it for it. This issue is worse for DOS emulation (if we ever really get serious about that), since DOS programs aren't expecting "save yourself and restore the console to the default mode" messages, and couldn't process them if you sent them. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.