Message-ID:	<8D53104ECD0CD211AF4000A0C9D60AE32836D6@probe-2.Acclaim-Euro.net>
From:	Shawn Hargreaves <ShawnH AT Probe DOT co DOT uk>
To:	djgpp AT delorie DOT com
Subject:	Re: ALLEGRO: Vesa and Refresh rate
Date:	Fri, 13 Nov 1998 14:01:36 -0000
MIME-Version:	1.0
X-Mailer:	Internet Mail Service (5.0.1460.8)
Reply-To:	djgpp AT delorie DOT com

Manni Heumann writes:
> I often use Vesa 1 graphics mode 640x480. I need to influence the 
> refresh rate, not because I want flicker free displays, but because 
> I need to time the display very accurately.

Some video cards will come with a command line utility for setting the 
default retrace rate, but if you don't have one of these, I'm afraid 
you are out of luck. There is no standard way to control the refresh 
rate of a VESA 1.x driver, and although some functions for doing this 
were added in VESA 3.0, they aren't supported by Allegro, partly 
because I don't have any VBE 3.0 drivers for testing, and partly 
because the VBE 3.0 spec is not freely available, so I don't know how 
to use these functions.


	Shawn Hargreaves.

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