1.\" $OpenBSD: ahci.4,v 1.11 2013/07/16 16:05:48 schwarze 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.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.Dd $Mdocdate: July 16 2013 $ 18.Dt AHCI 4 19.Os 20.Sh NAME 21.Nm ahci 22.Nd Advanced Host Controller Interface for Serial ATA 23.Sh SYNOPSIS 24.Cd "ahci* at pci?" 25.Cd "ahci* at jmb?" 26.Sh DESCRIPTION 27The 28.Nm 29driver provides support for Serial ATA controllers conforming to the 30Advanced Host Controller Interface specification. 31.Pp 32Several AHCI capable controllers also provide a compatibility mode that 33causes them to appear as a traditional ATA controller supported by 34.Xr pciide 4 . 35.Pp 36Although 37.Nm 38controllers are actual ATA controllers, the driver emulates SCSI via a 39translation layer. 40.Pp 41Setting the lowest bit (0x1) of the driver flags forces 42.Nm 43to negotiate SATA 1 (1.5 Gb/s) transfer speeds only. 44It may be useful where higher speeds are unstable. 45.Sh SEE ALSO 46.Xr intro 4 , 47.Xr jmb 4 , 48.Xr pci 4 , 49.Xr pciide 4 , 50.Xr scsi 4 51.Sh HISTORY 52The 53.Nm 54driver first appeared in 55.Ox 4.1 . 56.Sh AUTHORS 57.An -nosplit 58The 59.Nm 60driver was written by 61.An David Gwynne Aq Mt dlg@openbsd.org 62and 63.An Christopher Pascoe Aq Mt pascoe@openbsd.org . 64