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 December 6, 2011 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.Pp 56.Bl -tag -width 4n -offset indent -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.Pp 77.Bl -tag -width 4n -offset indent -compact 78.It 0 79interface Power Management is disabled (default); 80.It 1 81device is allowed to initiate PM state change, host is passive; 82.It 2 83host initiates PARTIAL PM state transition every time port becomes idle; 84.It 3 85host initiates SLUMBER PM state transition every time port becomes idle. 86.It 4 87driver initiates PARTIAL PM state transition 1ms after port becomes idle; 88.It 5 89driver initiates SLUMBER PM state transition 125ms after port becomes idle. 90.El 91.Pp 92Some controllers, such as ICH8, do not implement modes 2 and 3 with NCQ used. 93Because of artificial entering latency, performance degradation in modes 944 and 5 is much smaller then in modes 2 and 3. 95.Pp 96Note that interface Power Management complicates device presence detection. 97A manual bus reset/rescan may be needed after device hot-plug, unless hardware 98implements Cold Presence Detection. 99.It Va hint.ahcich. Ns Ar X Ns Va .sata_rev 100setting to nonzero value limits maximum SATA revision (speed). 101Values 1, 2 and 3 are respectively 1.5, 3 and 6Gbps. 102.It Va hw.ahci.force 103setting to nonzero value forces driver attach to some known AHCI-capable 104chips even if they are configured for legacy IDE emulation. Default is 1. 105.El 106.Sh DESCRIPTION 107This driver provides the 108.Xr CAM 4 109subsystem with native access to the 110.Tn SATA 111ports of AHCI-compatible controllers. 112Each SATA port found is represented to CAM as a separate bus with one 113target, or, if HBA supports Port Multipliers, 16 targets. 114Most of the bus-management details are handled by the SATA-specific 115transport of CAM. 116Connected ATA disks are handled by the ATA protocol disk peripheral driver 117.Xr ada 4 . 118ATAPI devices are handled by the SCSI protocol peripheral drivers 119.Xr cd 4 , 120.Xr da 4 , 121.Xr sa 4 , 122etc. 123.Pp 124Driver features include support for Serial ATA and ATAPI devices, 125Port Multipliers (including FIS-based switching, when supported), 126hardware command queues (up to 32 commands per port), 127Native Command Queuing, SATA interface Power Management, device hot-plug 128and Message Signaled Interrupts. 129.Pp 130Driver supports "LED" enclosure management messages, defined by the AHCI. 131When supported by hardware, it allows to control per-port activity, locate 132and fault LEDs via the 133.Xr led 4 134API for localization and status reporting purposes. 135Supporting AHCI controllers may transmit that information to the backplane 136controllers via SGPIO interface. Backplane controllers interpret received 137statuses in some way (IBPI standard) to report them using present indicators. 138.Pp 139AHCI hardware is also supported by ataahci driver from 140.Xr ata 4 141subsystem. 142If both drivers are loaded at the same time, this one will be 143given precedence as the more functional of the two. 144.Sh HARDWARE 145The 146.Nm 147driver supports AHCI compatible controllers having PCI class 1 (mass storage), 148subclass 6 (SATA) and programming interface 1 (AHCI). 149.Pp 150Also, in cooperation with atamarvell and atajmicron drivers of ata(4), 151it supports AHCI part of legacy-PATA + AHCI-SATA combined controllers, 152such as JMicron JMB36x and Marvell 88SE61xx. 153.Sh FILES 154.Bl -tag -width /dev/led/ahcich*.locate 155.It Pa /dev/led/ahcich*.act 156activity LED device nodes 157.It Pa /dev/led/ahcich*.fault 158fault LED device nodes 159.It Pa /dev/led/ahcich*.locate 160locate LED device nodes 161.El 162.Sh SEE ALSO 163.Xr ada 4 , 164.Xr ata 4 , 165.Xr cam 4 , 166.Xr cd 4 , 167.Xr da 4 , 168.Xr sa 4 169.Sh HISTORY 170The 171.Nm 172driver first appeared in 173.Fx 8.0 . 174.Sh AUTHORS 175.An Alexander Motin Aq mav@FreeBSD.org . 176