From owner-freebsd-hackers Thu Feb 20 05:43:44 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id FAA12998 for hackers-outgoing; Thu, 20 Feb 1997 05:43:44 -0800 (PST) Received: from nic.follonett.no (nic.follonett.no [194.198.43.10]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id FAA12993 for ; Thu, 20 Feb 1997 05:43:36 -0800 (PST) Received: (from uucp@localhost) by nic.follonett.no (8.8.5/8.8.3) with UUCP id OAA12910; Thu, 20 Feb 1997 14:41:34 +0100 (MET) Received: from oo7 (oo7.dimaga.com [192.0.0.65]) by dimaga.com (8.8.5/8.7.2) with SMTP id OAA00671; Thu, 20 Feb 1997 14:29:38 +0100 (MET) Message-Id: <3.0.32.19970220142938.00b142d0@dimaga.com> X-Sender: eivind@dimaga.com X-Mailer: Windows Eudora Pro Version 3.0 (32) Date: Thu, 20 Feb 1997 14:29:39 +0100 To: Bruce Evans From: Eivind Eklund Subject: Re: Screen flickering Cc: brian@awfulhak.demon.co.uk, hackers@freebsd.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk At 09:42 PM 2/20/97 +1100, Bruce Evans wrote: >Disabling interrupts for a long time is unacceptable for a multitasking >OS. The problem can be handled "right" if the video card can generate >vertical retrace interrupts: > > 1. Make the vertical retrace interrupt handler a "fast" interrupt > handler so that it has a low latency and can't be interrupted. > Don't use too many other "fast" interrupt handlers, or the > interrupt latency might be too high. > 2. Program the sparkly registers in the vertical retrace interrupt > handler. Do this in less than 20 usec or someone will complain > that the interrupt latency is too high. > >Otherwise, the best that can be done is probably something like: Nope. If there is a *timer* interrupt available, you can use it to create a vertical blanking interrupt by tweaking start point and delay. 'Nuff said? Eivind Eklund perhaps@yes.no http://maybe.yes.no/perhaps/ eivind@freebsd.org