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1What: /sys/class/scsi_host/hostX/isci_id2Date: June 20113Contact: Dave Jiang <dave.jiang@intel.com>4Description:5 This file contains the enumerated host ID for the Intel6 SCU controller. The Intel(R) C600 Series Chipset SATA/SAS7 Storage Control Unit embeds up to two 4-port controllers in8 a single PCI device. The controllers are enumerated in order9 which usually means the lowest number scsi_host corresponds10 with the first controller, but this association is not11 guaranteed. The 'isci_id' attribute unambiguously identifies12 the controller index: '0' for the first controller,13 '1' for the second.14 15What: /sys/class/scsi_host/hostX/acciopath_status16Date: November 201317Contact: Stephen M. Cameron <scameron@beardog.cce.hp.com>18Description: This file contains the current status of the "SSD Smart Path"19 feature of HP Smart Array RAID controllers using the hpsa20 driver. SSD Smart Path, when enabled permits the driver to21 send i/o requests directly to physical devices that are part22 of a logical drive, bypassing the controllers firmware RAID23 stack for a performance advantage when possible. A value of24 '1' indicates the feature is enabled, and the controller may25 use the direct i/o path to physical devices. A value of zero26 means the feature is disabled and the controller may not use27 the direct i/o path to physical devices. This setting is28 controller wide, affecting all configured logical drives on the29 controller. This file is readable and writable.30 31What: /sys/class/scsi_host/hostX/link_power_management_policy32Date: Oct, 200733KernelVersion: v2.6.2434Contact: linux-ide@vger.kernel.org35Description:36 (RW) This parameter allows the user to read and set the link37 (interface) power management.38 39 There are four possible options:40 41 min_power: Tell the controller to try to make the link use the42 least possible power when possible. This may sacrifice some43 performance due to increased latency when coming out of lower44 power states.45 46 max_performance: Generally, this means no power management.47 Tell the controller to have performance be a priority over power48 management.49 50 medium_power: Tell the controller to enter a lower power state51 when possible, but do not enter the lowest power state, thus52 improving latency over min_power setting.53 54 med_power_with_dipm: Identical to the existing medium_power55 setting except that it enables dipm (device initiated power56 management) on top, which makes it match the Windows IRST (Intel57 Rapid Storage Technology) driver settings. This setting is also58 close to min_power, except that:59 60 a) It does not use host-initiated slumber mode, but it does61 allow device-initiated slumber62 b) It does not enable low power device sleep mode (DevSlp).63 64What: /sys/class/scsi_host/hostX/em_message65What: /sys/class/scsi_host/hostX/em_message_type66Date: Jun, 200867KernelVersion: v2.6.2768Contact: linux-ide@vger.kernel.org69Description:70 em_message: (RW) Enclosure management support. For the LED71 protocol, writes and reads correspond to the LED message format72 as defined in the AHCI spec.73 74 The user must turn sw_activity (under `/sys/block/*/device/`)75 OFF it they wish to control the activity LED via the em_message76 file.77 78 em_message_type: (RO) Displays the current enclosure management79 protocol that is being used by the driver (for eg. LED, SAF-TE,80 SES-2, SGPIO etc).81 82What: /sys/class/scsi_host/hostX/ahci_port_cmd83What: /sys/class/scsi_host/hostX/ahci_host_caps84What: /sys/class/scsi_host/hostX/ahci_host_cap285Date: Mar, 201086KernelVersion: v2.6.3587Contact: linux-ide@vger.kernel.org88Description:89 [to be documented]90 91What: /sys/class/scsi_host/hostX/ahci_host_version92Date: Mar, 201093KernelVersion: v2.6.3594Contact: linux-ide@vger.kernel.org95Description:96 (RO) Display the version of the AHCI spec implemented by the97 host.98 99What: /sys/class/scsi_host/hostX/em_buffer100Date: Apr, 2010101KernelVersion: v2.6.35102Contact: linux-ide@vger.kernel.org103Description:104 (RW) Allows access to AHCI EM (enclosure management) buffer105 directly if the host supports EM.106 107 For eg. the AHCI driver supports SGPIO EM messages but the108 SATA/AHCI specs do not define the SGPIO message format of the EM109 buffer. Different hardware(HW) vendors may have different110 definitions. With the em_buffer attribute, this issue can be111 solved by allowing HW vendors to provide userland drivers and112 tools for their SGPIO initiators.113 114What: /sys/class/scsi_host/hostX/em_message_supported115Date: Oct, 2009116KernelVersion: v2.6.39117Contact: linux-ide@vger.kernel.org118Description:119 (RO) Displays supported enclosure management message types.120