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.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd January 28, 2010 28.Dt AHCI 4 29.Os 30.Sh NAME 31.Nm ahci 32.Nd Serial ATA Advanced Host Controller Interface driver 33.Sh SYNOPSIS 34To compile this driver into the kernel, 35place the following lines in your 36kernel configuration file: 37.Bd -ragged -offset indent 38.Cd "device pci" 39.Cd "device scbus" 40.Cd "device ahci" 41.Ed 42.Pp 43Alternatively, to load the driver as a 44module at boot time, place the following line in 45.Xr loader.conf 5 : 46.Bd -literal -offset indent 47ahci_load="YES" 48.Ed 49.Pp 50The following tunables are settable from the 51.Xr loader 8 : 52.Bl -ohang 53.It Va hint.ahci. Ns Ar X Ns Va .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. Ns Ar X Ns Va .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. Ns Ar X Ns Va .pm_level 71controls SATA interface Power Management for the 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. 95A manual bus reset is needed on device hot-plug. 96.It Va hint.ahcich. Ns Ar X Ns Va .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 102.Xr CAM 4 103subsystem with native access to the 104.Tn SATA 105ports of AHCI-compatible controllers. 106Each SATA port found is represented to CAM as a separate bus with one 107target, or, if HBA supports Port Multipliers, 16 targets. 108Most of the bus-management details are handled by the SATA-specific 109transport of CAM. 110Connected ATA disks are handled by the ATA protocol disk peripheral driver 111.Xr ada 4 . 112ATAPI devices are handled by the SCSI protocol peripheral drivers 113.Xr cd 4 , 114.Xr da 4 , 115.Xr sa 4 , 116etc. 117.Pp 118Driver features include support for Serial ATA and ATAPI devices, 119Port Multipliers (including FIS-based switching, when supported), 120hardware command queues (up to 32 commands per port), 121Native Command Queuing, SATA interface Power Management, device hot-plug 122and Message Signaled Interrupts. 123.Pp 124AHCI hardware is also supported by ataahci driver from 125.Xr ata 4 126subsystem. 127If both drivers are loaded at the same time, this one will be 128given precedence as the more functional of the two. 129.Sh HARDWARE 130The 131.Nm 132driver supports AHCI compatible controllers having PCI class 1 (mass storage), 133subclass 6 (SATA) and programming interface 1 (AHCI). 134.Pp 135Also, in cooperation with atamarvell and atajmicron drivers of ata(4), 136it supports AHCI part of legacy-PATA + AHCI-SATA combined controllers, 137such as JMicron JMB36x and Marvell 88SX61xx. 138.Sh SEE ALSO 139.Xr ada 4 , 140.Xr ata 4 , 141.Xr cam 4 , 142.Xr cd 4 , 143.Xr da 4 , 144.Xr sa 4 145.Sh HISTORY 146The 147.Nm 148driver first appeared in 149.Fx 8.0 . 150.Sh AUTHORS 151.An Alexander Motin Aq mav@FreeBSD.org . 152