Path: utzoo!censor!geac!torsqnt!lethe!telly!attcan!uunet!stanford.edu!rutgers!att!cbnewsh!rkl
From: rkl@cbnewsh.att.com (kevin.laux)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Dual Monitor Switching
Message-ID: <1991Mar12.133739.28811@cbnewsh.att.com>
Date: 12 Mar 91 13:37:39 GMT
References: <1991Mar11.172914.4450@engin.umich.edu>
Distribution: na
Organization: AT&T Bell Laboratories
Lines: 36

In article <1991Mar11.172914.4450@engin.umich.edu>, pong@caen.engin.umich.edu (Bryan John Jalowitz) writes:
> 
> Hi,
> I would like to know how, from within an application, I can switch
> monitors in a dual configuration.  I would like something similar to
> "mode mono" vs. "mode co80", but that does not clear the display.
> 
> More specifically, I am using a VGA/HERC dual monitor configuration,
> and I would like to be able to route text/graphics to one or the other
> display systems.  I know about setting the mode with int 10h func 0,
> but there appears to be more to it than that.  That doesn't "switch" the
> video bios' notion of the current display.
> 
> What am I missing here?

	You're missing Int 10h Function 12h Subfunction 35h, the Display
Switch Interface.

	AH:	12h
	BL:	35h
	AL:	0	Initial external adapter off
		1	Initial VGA on
		2	Active adapter off
		3	Inactive adapter on
	ES:	Segment of Switch State area
	DX:	Offset of Switch State area

	The first time you switch displays you must use AL=0,1.  After that,
you use a double call to AL=2,3.  The Switch state area is a 128 byte buffer
and each display needs it own.

-- 
________________________________________________________________________________
	R. Kevin Laux				Email: rkl1@hound.att.com
	AT&T Bell Labs				Voice: (908) 949-1160
	Holmdel, NJ 07733			Fax:   (908) 949-0959