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DVBOX(4)             NetBSD/hp300 Kernel Interfaces Manual            DVBOX(4)


NAME

     dvbox -- HP98730 ``DaVinci'' graphics device interface


DESCRIPTION

     This driver is for the HP98730 and 98731 graphics device, also known as
     the DaVinci.  This driver has not been tested with all possible combina-
     tions 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.

     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.  The hardware installation manual
     describes the procedure for setting these values.

     A user process communicates to the device initially by means of ioctl(2)
     calls.  For the HP-UX ioctl(2) calls supported, refer to HP-UX manuals.
     The BSD calls supported are:

     GRFIOCGINFO
             Get Graphics Info

             Get info about device, setting the entries in the grfinfo struc-
             ture, as defined in <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.

     GRFIOCON
             Graphics On

             Turn graphics on by enabling CRT output.  The screen will come
             on, displaying whatever is in the frame buffer, using whatever
             colormap is in place.

     GRFIOCOFF
             Graphics Off

             Turn graphics off by disabling output to the CRT.  The frame
             buffer contents are not affected.

     GRFIOCMAP
             Map Device to user space

             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 <hpdev/grf_dvreg.h>.


FILES

     /dev/grf?          BSD special file
     /dev/crt98730
     /dev/ocrt98730     HP-UX starbase special files
     /dev/MAKEDEV.hpux  script for creating HP-UX special files


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 `grf0':

           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 */


DIAGNOSTICS

     None under BSD.  HP-UX CE.utilities must be used.


ERRORS

     [ENODEV]  no such device.

     [EBUSY]   Another process has the device open.

     [EINVAL]  Invalid ioctl specification.


SEE ALSO

     ioctl(2), grf(4)


BUGS

     Not tested for all configurations of scan board and frame buffer memory
     boards.

NetBSD 5.2                       June 9, 1993                       NetBSD 5.2