90 lines
3.3 KiB
Groff
90 lines
3.3 KiB
Groff
.\" Copyright (c) 1983, 1991 Regents of the University of California.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" from: @(#)ik.4 6.2 (Berkeley) 3/27/91
|
|
.\" $Id: ik.4,v 1.2 1993/08/01 07:36:15 mycroft Exp $
|
|
.\"
|
|
.Dd March 27, 1991
|
|
.Dt IK 4 vax
|
|
.Os BSD 4.2
|
|
.Sh NAME
|
|
.Nm ik
|
|
.Nd "Ikonas frame buffer, graphics device interface"
|
|
.Sh SYNOPSIS
|
|
.Cd "device ik0 at uba? csr 0172460 vector ikintr"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm ik
|
|
driver
|
|
provides an interface to an Ikonas frame buffer graphics device.
|
|
Each minor device is a different frame buffer interface board.
|
|
When the device is opened, its interface registers are mapped,
|
|
via virtual memory, into the user processes address space.
|
|
This allows the user process very high bandwidth to the frame buffer
|
|
with no system call overhead.
|
|
.Pp
|
|
Bytes written or read from the device are
|
|
.Tn DMA Ns 'ed
|
|
from or to the interface.
|
|
The frame buffer
|
|
.Tn XY
|
|
address, its addressing mode, etc. must be set up by the
|
|
user process before calling write or read.
|
|
.Pp
|
|
Other communication with the driver is via ioctls.
|
|
The
|
|
.Dv IK_GETADDR
|
|
.Xr ioctl 2
|
|
returns the virtual address where the user process can
|
|
find the interface registers.
|
|
The
|
|
.Dv IK_WAITINT
|
|
.Xr ioctl
|
|
suspends the user process until the ikonas device
|
|
has interrupted (for whatever reason \(em the user process has to set
|
|
the interrupt enables).
|
|
.Sh FILES
|
|
.Bl -tag -width /dev/ikxx -compact
|
|
.It Pa /dev/ik
|
|
.El
|
|
.Sh DIAGNOSTICS
|
|
None.
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
driver appeared in
|
|
.Bx 4.2 .
|
|
.Sh BUGS
|
|
An invalid access (e.g., longword) to a mapped interface register
|
|
can cause the system to crash with a machine check.
|
|
A user process could possibly cause infinite interrupts hence
|
|
bringing things to a crawl.
|