From owner-freebsd-hackers Sat Dec 17 16:28:57 1994 Return-Path: hackers-owner Received: (from root@localhost) by freefall.cdrom.com (8.6.8/8.6.6) id QAA21884 for hackers-outgoing; Sat, 17 Dec 1994 16:28:57 -0800 Received: from cs.weber.edu (cs.weber.edu [137.190.16.16]) by freefall.cdrom.com (8.6.8/8.6.6) with SMTP id QAA21878 for ; Sat, 17 Dec 1994 16:28:54 -0800 Received: by cs.weber.edu (4.1/SMI-4.1.1) id AA26627; Sat, 17 Dec 94 17:24:08 MST From: terry@cs.weber.edu (Terry Lambert) Message-Id: <9412180024.AA26627@cs.weber.edu> Subject: Re: syscons & multiple Xservers? To: dawes@physics.su.oz.au (David Dawes) Date: Sat, 17 Dec 94 17:24:07 MST Cc: kaleb@x.org, hackers@freebsd.org In-Reply-To: <199412160146.AA10014@physics.su.OZ.AU>; from "David Dawes" at Dec 16, 94 12:46 pm X-Mailer: ELM [version 2.3 PL11] Sender: hackers-owner@freebsd.org Precedence: bulk [ ... multiple X servers with just one console ... ] > The race condition is when two servers try to initialise the video > hardware at the same time. It should be possible to prevent the second > one from accessing the hardware until the first one has got the point > where it can allow a VT switch providing that there is at least a little > delay between when they start. I don't know if this requires changes > in syscons, XFree86 or both (I suspect both). This worked fine in 1.1. It's the console interface that changed. I suspect no X changes are needed. The problem is that locking the resource is necessary, and you have to lock it over the entire critical section. Right now the critical sections are allowed to interleave. In point of fact, you *can* start up two servers. You just have to *never* switch directly between the servers without switching to a vanilla console in between. Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.