From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Richard Cooper" Subject: video sync timing Date: Sat, 27 Aug 2005 15:28:20 -0400 Message-ID: Mime-Version: 1.0 Content-Transfer-Encoding: 7BIT Return-path: Sender: linux-assembly-owner@vger.kernel.org List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed delsp=yes" To: linux-assembly@vger.kernel.org Any ideas how I might sync to bit 3 of port 0x3DA, the video card's vertical sync signal? Just watching the bit in a loop doesn't seem like a good idea, since the CPU could be off doing something else, but as far as I know any timer function I might use will only be accurate to 1/100 of a second, which wouldn't be much better than watching the bit in a loop. Since things like DOOM run in Linux, I think there must be some way to do it. I've discovered that simutaneously changing the screen data and the color palette without synchronization creates a flicker of a mess on the screen, and DOOM doesn't do that in Linux, so I guess it must be synchronizing somehow.