RB(4)                 OpenBSD Programmer's Manual (HP300)                RB(4)

NAME
     rb - HP98720 ``Renaissance'' device interface

DESCRIPTION
     This driver is for the HP98720 and 98721 graphics device, also known as
     the Renaissance.  This driver has not been tested with all possible com-
     binations 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 Renaissance 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 cons(4)). The hardware in-
     stallation 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 98720,
             the number of planes should be 4.  The number of colors would
             therefore be 15, excluding black.  If one 98722A 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 98722 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 framebuffer space. Once the device
             file is mapped, the frame buffer structure is accessible.  The
             structure describing the 98720 is defined in hpdev/grf_rbreg.h.

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 rboxfb *rbox;
     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;
     }
     rbox = (rboxfb *) Addr;                         /* Control Registers   */
     frame_buffer = (u_char *) Addr + gi.gd_regsize; /* Frame buffer memory */

FILES
     /dev/grf?          BSD special file
     /dev/crt98720
     /dev/ocrt98720     HP-UX starbase special files
     /dev/MAKEDEV.hpux  script for creating HP-UX special files

DIAGNOSTICS
     None under BSD. The 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)

     For extensive code examples using the Renaissance, see the X device de-
     pendent source.

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

OpenBSD 3.0                      June 9, 1993                                2
