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 52.Xr loader 8 : 53.Bl -ohang 54.It Va hint.ahci. Ns Ar X Ns Va .msi 55controls Message Signaled Interrupts (MSI) usage by the specified controller 56.Bl -tag -compact 57.It 0 58MSI disabled; 59.It 1 60single MSI vector used, if supported (default); 61.It 2 62multiple MSI vectors used, if supported; 63.El 64.It Va hint.ahci. Ns Ar X Ns Va .ccc 65controls Command Completion Coalescing (CCC) usage by the specified controller. 66Non-zero value enables CCC and defines maximum time (in ms), request can wait 67for interrupt, if there are some more requests present on controller queue. 68CCC reduces number of context switches on systems with many parallel requests, 69but it can decrease disk performance on some workloads due to additional 70command latency. 71.It Va hint.ahcich. Ns Ar X Ns Va .pm_level 72controls SATA interface Power Management for the specified channel, 73allowing some power to be saved at the cost of additional command 74latency. 75Possible values: 76.Bl -tag -compact 77.It 0 78interface Power Management is disabled (default); 79.It 1 80device is allowed to initiate PM state change, host is passive; 81.It 2 82host initiates PARTIAL PM state transition every time port becomes idle; 83.It 3 84host initiates SLUMBER PM state transition every time port becomes idle. 85.It 4 86driver initiates PARTIAL PM state transition 1ms after port becomes idle; 87.It 5 88driver initiates SLUMBER PM state transition 125ms after port becomes idle. 89.El 90Some controllers, such as ICH8, do not implement modes 2 and 3 with NCQ used. 91Because of artificial entering latency, performance degradation in modes 924 and 5 is much smaller then in modes 2 and 3. 93.Pp 94Note that interface Power Management is not compatible with 95device presence detection. 96A manual bus reset is needed on device hot-plug. 97.It Va hint.ahcich. Ns Ar X Ns Va .sata_rev 98setting to nonzero value limits maximum SATA revision (speed). 99Values 1, 2 and 3 are respectively 1.5, 3 and 6Gbps. 100.El 101.Sh DESCRIPTION 102This driver provides the 103.Xr CAM 4 104subsystem with native access to the 105.Tn SATA 106ports of AHCI-compatible controllers. 107Each SATA port found is represented to CAM as a separate bus with one 108target, or, if HBA supports Port Multipliers, 16 targets. 109Most of the bus-management details are handled by the SATA-specific 110transport of CAM. 111Connected ATA disks are handled by the ATA protocol disk peripheral driver 112.Xr ada 4 . 113ATAPI devices are handled by the SCSI protocol peripheral drivers 114.Xr cd 4 , 115.Xr da 4 , 116.Xr sa 4 , 117etc. 118.Pp 119Driver features include support for Serial ATA and ATAPI devices, 120Port Multipliers (including FIS-based switching, when supported), 121hardware command queues (up to 32 commands per port), 122Native Command Queuing, SATA interface Power Management, device hot-plug 123and Message Signaled Interrupts. 124.Pp 125AHCI hardware is also supported by ataahci driver from 126.Xr ata 4 127subsystem. 128If both drivers are loaded at the same time, this one will be 129given precedence as the more functional of the two. 130.Sh HARDWARE 131The 132.Nm 133driver supports AHCI compatible controllers having PCI class 1 (mass storage), 134subclass 6 (SATA) and programming interface 1 (AHCI). 135.Pp 136Also, in cooperation with atamarvell and atajmicron drivers of ata(4), 137it supports AHCI part of legacy-PATA + AHCI-SATA combined controllers, 138such as JMicron JMB36x and Marvell 88SX61xx. 139.Sh SEE ALSO 140.Xr ada 4 , 141.Xr ata 4 , 142.Xr cam 4 , 143.Xr cd 4 , 144.Xr da 4 , 145.Xr sa 4 146.Sh HISTORY 147The 148.Nm 149driver first appeared in 150.Fx 8.0 . 151.Sh AUTHORS 152.An Alexander Motin Aq mav@FreeBSD.org . 153