.\"	$OpenBSD: dv.4,v 1.6 2001/11/13 13:54:26 mpech Exp $
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.\" Copyright (c) 1990, 1991, 1993
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.\" This code is derived from software contributed to Berkeley by
.\" the Systems Programming Group of the University of Utah Computer
.\" Science Department.
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.\"     from: @(#)dv.4	8.1 (Berkeley) 6/9/93
.\"
.Dd June 9, 1993
.Dt DV 4 hp300
.Os
.Sh NAME
.Nm dv
.Nd
.Tn HP98730
``DaVinci'' device interface
.Sh DESCRIPTION
This driver is for the
.Tn HP98730
and 98731 graphics device, also known as
the DaVinci.
This driver has not been tested with all possible combinations of frame
buffer boards and scan boards installed in the device.
The driver merely checks for the existence of the device and does minimal set
up.
.Pp
The DaVinci can be configured at either the ``internal'' address
(frame buffer address 0x200000, control register space address 0x560000)
or at an external select code less than 32.
At the internal address it will be the ``preferred'' console device
(see
.Xr cons 4 ) .
The hardware installation manual describes the procedure for
setting these values.
.Pp
A user process communicates to the device initially by means of
.Xr ioctl 2
calls.
For the
.Tn HP-UX
.Xr ioctl 2
calls supported, refer to
.Tn HP-UX
manuals.
The
.Bx
calls supported are:
.Bl -tag -width indent
.It Dv GRFIOCGINFO
Get Graphics Info
.Pp
Get info about device, setting the entries in the
.Ar grfinfo
structure, as defined in
.Aq Pa hpdev/grfioctl.h .
For the standard 98730, the number of planes should be 4.
The number of colors would therefore be 15, excluding black.
If one 98732A frame buffer board is installed, there will still be 4 planes, 
with the 4 planes on the colormap board becoming overlay planes.
With each additional 98732 frame buffer board 4 planes will be added up
to a maximum of 32 planes total.
.It Dv GRFIOCON
Graphics On
.Pp
Turn graphics on by enabling
.Tn CRT
output.
The screen will come on, displaying whatever is in the frame buffer, using
whatever colormap is in place.
.It Dv GRFIOCOFF
Graphics Off
.Pp
Turn graphics off by disabling output to the
.Tn CRT .
The frame buffer contents
are not affected.
.It Dv GRFIOCMAP
Map Device to user space
.Pp
Map in control registers and frame buffer space.
Once the device file is mapped, the frame buffer structure is accessible.
The structure describing the 98730 is defined in
.Aq Pa hpdev/grf_dvreg.h .
.El
.Sh EXAMPLES
This is a short segment of code showing how the device is opened and mapped
into user process address space assuming that it is
.Ql grf0 :
.Bd -literal -offset indent
struct dvboxfb *dvbox;
u_char *Addr, frame_buffer;
struct grfinfo gi;
int disp_fd;

disp_fd = open("/dev/grf0",1);

if (ioctl (disp_fd, GRFIOCGINFO, &gi) < 0) return -1;

(void) ioctl (disp_fd, GRFIOCON, 0);

Addr = (u_char *) 0;
if (ioctl (disp_fd, GRFIOCMAP, &Addr) < 0) {
(void) ioctl (disp_fd, GRFIOCOFF, 0);
return -1;
}
dvbox = (dvboxfb *) Addr;                  /* Control Registers   */
frame_buffer=(u_char *)Addr+gi.gd_regsize; /* Frame buffer memory */
.Ed
.Sh FILES
.Bl -tag -width /dev/MAKEDEV.hpux -compact
.It Pa /dev/grf?
.Bx
special file
.It Pa /dev/crt98730
.It Pa /dev/ocrt98730
.Tn HP-UX
.Em starbase
special files
.It Pa /dev/MAKEDEV.hpux
script for creating
.Tn HP-UX
special files
.El
.Sh DIAGNOSTICS
None under
.Bx .
.Tn HP-UX
.Tn CE.utilities
must be used.
.Sh ERRORS
.Bl -tag -width [EINVAL]
.It Bq Er ENODEV
no such device.
.It Bq Er EBUSY
Another process has the device open.
.It Bq Er EINVAL
Invalid ioctl specification.
.El
.Sh SEE ALSO
.Xr ioctl 2 ,
.Xr grf 4
.Sh BUGS
Not tested for all configurations of scan board and frame buffer memory boards.