1.\" Copyright (c) 2009 Alexander Motin <mav@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. The name of the author may not be used to endorse or promote products 13.\" derived from this software without specific prior written permission. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd January 28, 2010 29.Dt AHCI 4 30.Os 31.Sh NAME 32.Nm ahci 33.Nd Serial ATA Advanced Host Controller Interface driver 34.Sh SYNOPSIS 35To compile this driver into the kernel, 36place the following lines in your 37kernel configuration file: 38.Bd -ragged -offset indent 39.Cd "device pci" 40.Cd "device scbus" 41.Cd "device ahci" 42.Ed 43.Pp 44Alternatively, to load the driver as a 45module at boot time, place the following line in 46.Xr loader.conf 5 : 47.Bd -literal -offset indent 48ahci_load="YES" 49.Ed 50.Pp 51The following tunables are settable from the loader: 52.Bl -ohang 53.It Va hint.ahci.X.msi 54controls Message Signaled Interrupts (MSI) usage by the specified controller 55.Bl -tag -compact 56.It 0 57MSI disabled; 58.It 1 59single MSI vector used, if supported (default); 60.It 2 61multiple MSI vectors used, if supported; 62.El 63.It Va hint.ahci.X.ccc 64controls Command Completion Coalescing (CCC) usage by the specified controller. 65Non-zero value enables CCC and defines maximum time (in ms), request can wait 66for interrupt, if there are some more requests present on controller queue. 67CCC reduces number of context switches on systems with many parallel requests, 68but it can decrease disk performance on some workloads due to additional 69command latency. 70.It Va hint.ahcich.X.pm_level 71controls SATA interface Power Management for specified channel, 72allowing some power to be saved at the cost of additional command 73latency. 74Possible values: 75.Bl -tag -compact 76.It 0 77interface Power Management is disabled (default); 78.It 1 79device is allowed to initiate PM state change, host is passive; 80.It 2 81host initiates PARTIAL PM state transition every time port becomes idle; 82.It 3 83host initiates SLUMBER PM state transition every time port becomes idle. 84.It 4 85driver initiates PARTIAL PM state transition 1ms after port becomes idle; 86.It 5 87driver initiates SLUMBER PM state transition 125ms after port becomes idle. 88.El 89Some controllers, such as ICH8, do not implement modes 2 and 3 with NCQ used. 90Because of artificial entering latency, performance degradation in modes 914 and 5 is much smaller then in modes 2 and 3. 92.Pp 93Note that interface Power Management is not compatible with 94device presence detection. 95You will have to reset bus manually on device hot-plug. 96.It Va hint.ahcich.X.sata_rev 97setting to nonzero value limits maximum SATA revision (speed). 98Values 1, 2 and 3 are respectively 1.5, 3 and 6Gbps. 99.El 100.Sh DESCRIPTION 101This driver provides the CAM subsystem with native access to the 102.Tn SATA 103ports of AHCI-compatible controllers. 104Each SATA port found is represented to CAM as a separate bus with one 105target, or, if HBA supports Port Multipliers, 16 targets. 106Most of the bus-management details are handled by the SATA-specific 107transport of CAM. 108Connected ATA disks are handled by the ATA protocol disk peripheral driver 109.Xr ada 4 . 110ATAPI devices are handled by the SCSI protocol peripheral drivers 111.Xr cd 4 , 112.Xr da 4 , 113.Xr sa 4 , 114etc. 115.Pp 116Driver features include support for Serial ATA and ATAPI devices, 117Port Multipliers (including FIS-based switching, when supported), 118hardware command queues (up to 32 commands per port), 119Native Command Queuing, SATA interface Power Management, device hot-plug 120and Message Signaled Interrupts. 121.Pp 122AHCI hardware is also supported by ataahci driver from 123.Xr ata 4 124subsystem. If both drivers are loaded at the same time, this one will be 125given precedence as the more functional of the two. 126.Sh HARDWARE 127The 128.Nm 129driver supports AHCI compatible controllers having PCI class 1 (mass storage), 130subclass 6 (SATA) and programming interface 1 (AHCI). 131.Pp 132Also, in cooperation with atamarvell and atajmicron drivers of ata(4), 133it supports AHCI part of legacy-PATA + AHCI-SATA combined controllers, 134such as JMicron JMB36x and Marvell 88SX61xx. 135.Sh SEE ALSO 136.Xr ada 4 , 137.Xr cd 4 , 138.Xr da 4 , 139.Xr sa 4 , 140.Xr scsi 4 , 141.Xr ata 4 142.Sh HISTORY 143The 144.Nm 145driver first appeared in 146.Fx 8.0 . 147.Sh AUTHORS 148.An Alexander Motin Aq mav@FreeBSD.org . 149