From owner-freebsd-current Thu Nov 4 17:13: 3 1999 Delivered-To: freebsd-current@freebsd.org Received: from herring.nlsystems.com (nlsys.demon.co.uk [158.152.125.33]) by hub.freebsd.org (Postfix) with ESMTP id B7476156AC for ; Thu, 4 Nov 1999 17:12:50 -0800 (PST) (envelope-from dfr@nlsystems.com) Received: from salmon.nlsystems.com (salmon.nlsystems.com [10.0.0.3]) by herring.nlsystems.com (8.9.3/8.8.8) with ESMTP id BAA73384; Fri, 5 Nov 1999 01:13:07 GMT (envelope-from dfr@nlsystems.com) Date: Fri, 5 Nov 1999 01:13:07 +0000 (GMT) From: Doug Rabson To: Amancio Hasty Cc: Soren Schmidt , Kazutaka YOKOTA , current@freebsd.org Subject: Re: vga driver and signal In-Reply-To: <199911041801.KAA46924@rah.star-gate.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Thu, 4 Nov 1999, Amancio Hasty wrote: > > It seems Kazutaka YOKOTA wrote: > > > > > > AFAIK, not all video cards generate the vertical retrace interrupt. > > > Even worse, some BIOSes have a configuration option which instract the > > > BIOS NOT to assign an IRQ to the PCI video card. > > > > > > I fully agree that the vertical retrace interrupt will be of great > > > value, but I wonder if it is really worth the trouble, because it might > > > be available in only few cards and systems at the end of the day... > > > > > > Well, I may be wrong :-) > > > > Well, sortof :) > > > > The delay caused by the system to process the interrupt and deliver > > the signal etc is unpredictable (well sortof) and is almost certainly > > too long so the window of opportunity will be missed ... > > > > This has been discussed to death many times in the past for the > > mouse pointer updates etc etc... > > > > Let me ask a different question: How does Microsoft's DirectX handle delivery > of vertical retrace interrupt? It doesn't. DX8 might deal with this, I'm not sure. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 442 9037 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message