1 What: /sys/class/scsi_host/hostX/isci_id 2 Date: June 2011 3 Contact: Dave Jiang <dave.jiang@intel.com> 4 Description: 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 15 What: /sys/class/scsi_host/hostX/acciopath_status 16 Date: November 2013 17 Contact: Stephen M. Cameron <scameron@beardog.cce.hp.com> 18 Description: 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 31 What: /sys/class/scsi_host/hostX/link_power_management_policy 32 Date: Oct, 2007 33 KernelVersion: v2.6.24 34 Contact: linux-ide@vger.kernel.org 35 Description: 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 60 a) It does not use host-initiated slumber mode, but it does 61 allow device-initiated slumber 62 b) It does not enable low power device sleep mode (DevSlp). 63 64 What: /sys/class/scsi_host/hostX/em_message 65 What: /sys/class/scsi_host/hostX/em_message_type 66 Date: Jun, 2008 67 KernelVersion: v2.6.27 68 Contact: linux-ide@vger.kernel.org 69 Description: 70 em_message: (RW) Enclosure management support. For the LED 71 protocol, writes and reads correspond to the LED message format 72 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_message 76 file. 77 78 em_message_type: (RO) Displays the current enclosure management 79 protocol that is being used by the driver (for eg. LED, SAF-TE, 80 SES-2, SGPIO etc). 81 82 What: /sys/class/scsi_host/hostX/ahci_port_cmd 83 What: /sys/class/scsi_host/hostX/ahci_host_caps 84 What: /sys/class/scsi_host/hostX/ahci_host_cap2 85 Date: Mar, 2010 86 KernelVersion: v2.6.35 87 Contact: linux-ide@vger.kernel.org 88 Description: 89 [to be documented] 90 91 What: /sys/class/scsi_host/hostX/ahci_host_version 92 Date: Mar, 2010 93 KernelVersion: v2.6.35 94 Contact: linux-ide@vger.kernel.org 95 Description: 96 (RO) Display the version of the AHCI spec implemented by the 97 host. 98 99 What: /sys/class/scsi_host/hostX/em_buffer 100 Date: Apr, 2010 101 KernelVersion: v2.6.35 102 Contact: linux-ide@vger.kernel.org 103 Description: 104 (RW) Allows access to AHCI EM (enclosure management) buffer 105 directly if the host supports EM. 106 107 For eg. the AHCI driver supports SGPIO EM messages but the 108 SATA/AHCI specs do not define the SGPIO message format of the EM 109 buffer. Different hardware(HW) vendors may have different 110 definitions. With the em_buffer attribute, this issue can be 111 solved by allowing HW vendors to provide userland drivers and 112 tools for their SGPIO initiators. 113 114 What: /sys/class/scsi_host/hostX/em_message_supported 115 Date: Oct, 2009 116 KernelVersion: v2.6.39 117 Contact: linux-ide@vger.kernel.org 118 Description: 119 (RO) Displays supported enclosure management message types.
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