1.\" $NetBSD: gio.4,v 1.19 2007/02/20 08:31:08 wiz Exp $ 2.\" 3.\" Copyright (c) 2002 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This document is derived from work contributed to The NetBSD Foundation 7.\" by Antti Kantee. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS BE 29.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.Dd December 25, 2006 38.Dt GIO 4 sgimips 39.Os 40.Sh NAME 41.Nm gio 42.Nd SGI's Graphics I/O (GIO) bus (an early PCI-like bus) 43.Sh SYNOPSIS 44.Cd "gio0 at imc0" 45.Cd "gio0 at pic0" 46.Sh DESCRIPTION 47The 48.Nm 49bus is a bus for connecting high-speed peripherals to the main memory and 50CPU. 51The devices themselves are typically (but not necessarily) connected to the 52.Xr hpc 4 53peripheral controller, and memory and CPU are accessed through the 54.Xr imc 4 55(Indy Memory Controller) or 56.Xr pic 4 57(Processor Interface Controller). 58The 59.Nm 60bus is found on the Personal Iris 4D/3x, Indigo, Indy, Challenge S, 61Challenge M, and Indigo2 machines and exists in three incarnations: 62GIO32, GIO32-bis, and GIO64. 63.Sh SEE ALSO 64.Xr giopci 4 , 65.Xr grtwo 4 , 66.Xr hpc 4 , 67.Xr imc 4 , 68.Xr light 4 , 69.Xr newport 4 , 70.Xr pic 4 71.Sh HISTORY 72The 73.Nm 74driver first appeared in 75.Nx 1.5 . 76.Sh CAVEATS 77Challenge S systems may use only one 78.Nm 79DMA-capable expansion card, despite having two slots. 80Cards based on the 81.Xr hpc 4 82controller, such as the GIO32 scsi and E++ Ethernet adapters, must be 83placed in slot 1 (closest to the side of the case). 84All other cards must be placed in slot 0 (adjacent to the memory banks). 85.Pp 86Indigo2 and Challenge M systems contain either three or four GIO64 connectors, 87depending on the model. 88However, in both cases only two electrically 89distinct slots are present. 90Therefore, distinct expansion cards may not 91share physical connectors associated with the same slot. 92Refer to the PCB 93stencils to determine the association between physical connectors and slots. 94.Sh BUGS 95Systems employing the 96.Xr imc 4 97may experience spurious SysAD bus parity errors when using expansion cards, 98which do not drive all data lines during a CPU PIO read. 99The only workaround is to disable SysAD parity checking when using such 100cards. 101