Date: Thu, 20 Feb 1997 14:29:39 +0100 From: Eivind Eklund <eivind@dimaga.com> To: Bruce Evans <bde@zeta.org.au> Cc: brian@awfulhak.demon.co.uk, hackers@freebsd.org Subject: Re: Screen flickering Message-ID: <3.0.32.19970220142938.00b142d0@dimaga.com>
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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
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