1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)ik.4 8.1 (Berkeley) 06/05/93 7.\" 8.Dd 9.Dt IK 4 vax 10.Os BSD 4.2 11.Sh NAME 12.Nm ik 13.Nd "Ikonas frame buffer, graphics device interface" 14.Sh SYNOPSIS 15.Cd "device ik0 at uba? csr 0172460 vector ikintr" 16.Sh DESCRIPTION 17The 18.Nm ik 19driver 20provides an interface to an Ikonas frame buffer graphics device. 21Each minor device is a different frame buffer interface board. 22When the device is opened, its interface registers are mapped, 23via virtual memory, into the user processes address space. 24This allows the user process very high bandwidth to the frame buffer 25with no system call overhead. 26.Pp 27Bytes written or read from the device are 28.Tn DMA Ns 'ed 29from or to the interface. 30The frame buffer 31.Tn XY 32address, its addressing mode, etc. must be set up by the 33user process before calling write or read. 34.Pp 35Other communication with the driver is via ioctls. 36The 37.Dv IK_GETADDR 38.Xr ioctl 2 39returns the virtual address where the user process can 40find the interface registers. 41The 42.Dv IK_WAITINT 43.Xr ioctl 44suspends the user process until the ikonas device 45has interrupted (for whatever reason \(em the user process has to set 46the interrupt enables). 47.Sh FILES 48.Bl -tag -width /dev/ikxx -compact 49.It Pa /dev/ik 50.El 51.Sh DIAGNOSTICS 52None. 53.Sh HISTORY 54The 55.Nm 56driver appeared in 57.Bx 4.2 . 58.Sh BUGS 59An invalid access (e.g., longword) to a mapped interface register 60can cause the system to crash with a machine check. 61A user process could possibly cause infinite interrupts hence 62bringing things to a crawl. 63