1.\" Copyright (c) 1983, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)ik.4 6.2 (Berkeley) 3/27/91 33.\" $Id: ik.4,v 1.2 1993/08/01 07:36:15 mycroft Exp $ 34.\" 35.Dd March 27, 1991 36.Dt IK 4 vax 37.Os BSD 4.2 38.Sh NAME 39.Nm ik 40.Nd "Ikonas frame buffer, graphics device interface" 41.Sh SYNOPSIS 42.Cd "device ik0 at uba? csr 0172460 vector ikintr" 43.Sh DESCRIPTION 44The 45.Nm ik 46driver 47provides an interface to an Ikonas frame buffer graphics device. 48Each minor device is a different frame buffer interface board. 49When the device is opened, its interface registers are mapped, 50via virtual memory, into the user processes address space. 51This allows the user process very high bandwidth to the frame buffer 52with no system call overhead. 53.Pp 54Bytes written or read from the device are 55.Tn DMA Ns 'ed 56from or to the interface. 57The frame buffer 58.Tn XY 59address, its addressing mode, etc. must be set up by the 60user process before calling write or read. 61.Pp 62Other communication with the driver is via ioctls. 63The 64.Dv IK_GETADDR 65.Xr ioctl 2 66returns the virtual address where the user process can 67find the interface registers. 68The 69.Dv IK_WAITINT 70.Xr ioctl 71suspends the user process until the ikonas device 72has interrupted (for whatever reason \(em the user process has to set 73the interrupt enables). 74.Sh FILES 75.Bl -tag -width /dev/ikxx -compact 76.It Pa /dev/ik 77.El 78.Sh DIAGNOSTICS 79None. 80.Sh HISTORY 81The 82.Nm 83driver appeared in 84.Bx 4.2 . 85.Sh BUGS 86An invalid access (e.g., longword) to a mapped interface register 87can cause the system to crash with a machine check. 88A user process could possibly cause infinite interrupts hence 89bringing things to a crawl. 90