1What: /sys/class/scsi_host/hostX/isci_id 2Date: June 2011 3Contact: Dave Jiang <dave.jiang@intel.com> 4Description: 5 This file contains the enumerated host ID for the Intel 6 SCU controller. The Intel(R) C600 Series Chipset SATA/SAS 7 Storage Control Unit embeds up to two 4-port controllers in 8 a single PCI device. The controllers are enumerated in order 9 which usually means the lowest number scsi_host corresponds 10 with the first controller, but this association is not 11 guaranteed. The 'isci_id' attribute unambiguously identifies 12 the controller index: '0' for the first controller, 13 '1' for the second. 14 15What: /sys/class/scsi_host/hostX/acciopath_status 16Date: November 2013 17Contact: 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 hpsa 20 driver. SSD Smart Path, when enabled permits the driver to 21 send i/o requests directly to physical devices that are part 22 of a logical drive, bypassing the controllers firmware RAID 23 stack for a performance advantage when possible. A value of 24 '1' indicates the feature is enabled, and the controller may 25 use the direct i/o path to physical devices. A value of zero 26 means the feature is disabled and the controller may not use 27 the direct i/o path to physical devices. This setting is 28 controller wide, affecting all configured logical drives on the 29 controller. This file is readable and writable. 30 31What: /sys/class/scsi_host/hostX/link_power_management_policy 32Date: Oct, 2007 33KernelVersion: v2.6.24 34Contact: linux-ide@vger.kernel.org 35Description: 36 (RW) This parameter allows the user to read and set the link 37 (interface) power management. 38 39 There are four possible options: 40 41 min_power: Tell the controller to try to make the link use the 42 least possible power when possible. This may sacrifice some 43 performance due to increased latency when coming out of lower 44 power states. 45 46 max_performance: Generally, this means no power management. 47 Tell the controller to have performance be a priority over power 48 management. 49 50 medium_power: Tell the controller to enter a lower power state 51 when possible, but do not enter the lowest power state, thus 52 improving latency over min_power setting. 53 54 med_power_with_dipm: Identical to the existing medium_power 55 setting except that it enables dipm (device initiated power 56 management) on top, which makes it match the Windows IRST (Intel 57 Rapid Storage Technology) driver settings. This setting is also 58 close to min_power, except that: 59 a) It does not use host-initiated slumber mode, but it does 60 allow device-initiated slumber 61 b) It does not enable low power device sleep mode (DevSlp). 62 63What: /sys/class/scsi_host/hostX/em_message 64What: /sys/class/scsi_host/hostX/em_message_type 65Date: Jun, 2008 66KernelVersion: v2.6.27 67Contact: linux-ide@vger.kernel.org 68Description: 69 em_message: (RW) Enclosure management support. For the LED 70 protocol, writes and reads correspond to the LED message format 71 as defined in the AHCI spec. 72 73 The user must turn sw_activity (under /sys/block/*/device/) OFF 74 it they wish to control the activity LED via the em_message 75 file. 76 77 em_message_type: (RO) Displays the current enclosure management 78 protocol that is being used by the driver (for eg. LED, SAF-TE, 79 SES-2, SGPIO etc). 80 81What: /sys/class/scsi_host/hostX/ahci_port_cmd 82What: /sys/class/scsi_host/hostX/ahci_host_caps 83What: /sys/class/scsi_host/hostX/ahci_host_cap2 84Date: Mar, 2010 85KernelVersion: v2.6.35 86Contact: linux-ide@vger.kernel.org 87Description: 88 [to be documented] 89 90What: /sys/class/scsi_host/hostX/ahci_host_version 91Date: Mar, 2010 92KernelVersion: v2.6.35 93Contact: linux-ide@vger.kernel.org 94Description: 95 (RO) Display the version of the AHCI spec implemented by the 96 host. 97 98What: /sys/class/scsi_host/hostX/em_buffer 99Date: Apr, 2010 100KernelVersion: v2.6.35 101Contact: linux-ide@vger.kernel.org 102Description: 103 (RW) Allows access to AHCI EM (enclosure management) buffer 104 directly if the host supports EM. 105 106 For eg. the AHCI driver supports SGPIO EM messages but the 107 SATA/AHCI specs do not define the SGPIO message format of the EM 108 buffer. Different hardware(HW) vendors may have different 109 definitions. With the em_buffer attribute, this issue can be 110 solved by allowing HW vendors to provide userland drivers and 111 tools for their SGPIO initiators. 112 113What: /sys/class/scsi_host/hostX/em_message_supported 114Date: Oct, 2009 115KernelVersion: v2.6.39 116Contact: linux-ide@vger.kernel.org 117Description: 118 (RO) Displays supported enclosure management message types. 119