1.\" $NetBSD: viaide.4,v 1.2 2003/10/08 13:39:11 wiz Exp $ 2.\" 3.\" Copyright (c) 2003 Manuel Bouyer. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. All advertising materials mentioning features or use of this software 14.\" must display the following acknowledgement: 15.\" This product includes software developed by Manuel Bouyer. 16.\" 4. The name of the author may not be used to endorse or promote products 17.\" derived from this software without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27.\" INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd October 8, 2003 31.Dt VIAIDE 4 32.Os 33.Sh NAME 34.Nm viaide 35.Nd AMD, NVIDIA and VIA IDE disk controllers driver 36.Sh SYNOPSIS 37.Cd "viaide* at pci? dev ? function ? flags 0x0000" 38.Cd "options PCIIDE_AMD756_ENABLEDMA" 39.Sh DESCRIPTION 40The 41.Nm 42driver supports the following IDE controllers 43and provides the interface with the hardware for the 44.Ic ata 45driver: 46.Bl -dash -compact -offset indent 47.It 48Advanced Micro Devices AMD-756, 766, and 768 IDE Controllers 49.It 50NVIDIA nForce and nForce2 51.It 52VIA Technologies VT82C586, VT82C586A, VT82C596A, VT82C686A, VT8233A, 53VT8235 and VT8237 IDE Controllers 54.El 55.Pp 56The 0x0002 flag forces the 57.Nm 58driver to disable DMA on chipsets for which DMA would normally be 59enabled. 60This can be used as a debugging aid, or to work around 61problems where the IDE controller is wired up to the system incorrectly. 62.Sh SEE ALSO 63.Xr ata 4 , 64.Xr atapi 4 , 65.Xr intro 4 , 66.Xr pci 4 , 67.Xr pciide 4 , 68.Xr wd 4 , 69.Xr wdc 4 70.Sh BUGS 71The AMD756 chip revision D2 has a bug affecting DMA (but not Ultra-DMA) 72modes. 73The workaround documented by AMD is to not use DMA on any drive which 74does not support Ultra-DMA modes. 75This does not appear to be necessary on all drives, the 76PCIIDE_AMD756_ENABLEDMA option can be used to force multiword DMA 77on the buggy revisions. 78Multiword DMA can eventually be disabled on a 79per-drive basis with config flags, see 80.Xr wd 4 . 81The bug, if triggered, will cause a total system hang. 82.Pp 83The timings used for the PIO and DMA modes for controllers listed above 84are for a PCI bus running at 30 or 33 MHz. 85This driver may not work properly on overclocked systems. 86