1.\" $OpenBSD: ahci.4,v 1.7 2008/04/19 01:18:39 djm Exp $ 2.\" 3.\" Copyright (c) 2006 David Gwynne <dlg@openbsd.org> 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" TORTIOUS ACTION, ARISING OUT OF 15.\" PERFORMANCE OF THIS SOFTWARE. 16.\" 17.\" Copyright (c) 2016 The DragonFly Project. All rights reserved. 18.\" 19.\" This code is derived from software contributed to The DragonFly Project 20.\" by Matthew Dillon <dillon@backplane.com> 21.\" 22.\" Redistribution and use in source and binary forms, with or without 23.\" modification, are permitted provided that the following conditions 24.\" are met: 25.\" 26.\" 1. Redistributions of source code must retain the above copyright 27.\" notice, this list of conditions and the following disclaimer. 28.\" 2. Redistributions in binary form must reproduce the above copyright 29.\" notice, this list of conditions and the following disclaimer in 30.\" the documentation and/or other materials provided with the 31.\" distribution. 32.\" 3. Neither the name of The DragonFly Project nor the names of its 33.\" contributors may be used to endorse or promote products derived 34.\" from this software without specific, prior written permission. 35.\" 36.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 37.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 38.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 39.\" FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 40.\" COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 41.\" INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 42.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 43.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 44.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 45.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 46.\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 47.\" SUCH DAMAGE. 48.\" 49.Dd November 28, 2014 50.Dt AHCI 4 51.Os 52.Sh NAME 53.Nm ahci 54.Nd Advanced Host Controller Interface for Serial ATA 55.Sh SYNOPSIS 56To compile this driver into the kernel, 57place the following line in your 58kernel configuration file: 59.Bd -ragged -offset indent 60.Cd "device ahci" 61.Ed 62.Pp 63Alternatively, to load the driver as a 64module at boot time, place the following line in 65.Xr loader.conf 5 : 66.Bd -literal -offset indent 67ahci_load="YES" 68.Ed 69.Sh DESCRIPTION 70The 71.Nm 72driver provides support for Serial ATA controllers conforming to the 73Advanced Host Controller Interface specification. 74.Pp 75Several AHCI capable controllers also provide a compatibility mode that 76causes them to appear as a traditional ATA controller supported by 77.Xr nata 4 . 78.Pp 79Although 80.Nm 81controllers are actual ATA controllers, the driver emulates SCSI via a 82translation layer. 83.Sh LOADER TUNABLES 84The following hints may be set in 85.Xr loader.conf 5 86to control the 87.Nm 88driver's behavior. 89Note that the hint need only exist, so removing it requires commenting it out. 90.Pp 91Usually both the 92.Xr nata 4 93and the 94.Nm 95drivers are loaded. 96The 97.Xr nata 4 98driver will pick up any ata-like devices which the 99.Nm 100driver misses. 101If the 102.Nm 103driver is disabled the 104.Xr nata 4 105driver will typically pick up the 106.Nm 107devices, albeit under the 108.Pa ad 109disk name rather than the 110.Pa da 111disk name. 112.Bd -literal -offset indent 113hint.ahci.disabled=1 114.Ed 115.Pp 116The 117.Nm 118driver can be told to force a lower-speed 1.5Gb link speed 119if necessary, and can also be told to refrain from attempting to send 120certain higher-level ATA commands to initialize ATA features which 121some devices might not properly implement. 122.Bd -literal -offset indent 123hint.ahci.force150=1 124hint.ahci.nofeatures=1 125.Ed 126.Pp 127By default, the driver will use MSI if it is supported. 128This behavior can be turned off by setting the following tunable: 129.Bd -literal -offset indent 130hw.ahci.msi.enable=0 131.Ed 132.Sh SYSCTL VARIABLES 133Link power management can be set with the sysctl 134.Va dev.ahci.%d.%d.link_pwr_mgmt 135to 0 for `disabled', 1 for `medium', and 2 for `aggressive'. 136Link power state can be read with the sysctl 137.Va dev.ahci.%d.%d.link_pwr_state . 138.Sh SEE ALSO 139.Xr intro 4 , 140.Xr nata 4 , 141.Xr pci 4 , 142.Xr scsi 4 , 143.Xr sili 4 , 144.Xr nvme 4 , 145.Xr loader.conf 5 146.Sh HISTORY 147The 148.Nm 149driver first appeared in 150.Dx 2.3 . 151.Sh AUTHORS 152.An -nosplit 153The 154.Nm 155driver was originally written by 156.An David Gwynne Aq Mt dlg@openbsd.org 157and 158.An Christopher Pascoe Aq Mt pascoe@openbsd.org 159for 160.Ox . 161.Pp 162It was ported to 163.Dx 164by 165.An Matt Dillon Aq Mt dillon@apollo.backplane.com , 166who substantially rewrote the driver (honestly, just about from scratch 167but having the openbsd code as a reference helped a lot), and 168added new features such as hot-plug and port multiplier support. 169