0001 What: /sys/class/scsi_host/hostX/isci_id
0002 Date: June 2011
0003 Contact: Dave Jiang <dave.jiang@intel.com>
0004 Description:
0005 This file contains the enumerated host ID for the Intel
0006 SCU controller. The Intel(R) C600 Series Chipset SATA/SAS
0007 Storage Control Unit embeds up to two 4-port controllers in
0008 a single PCI device. The controllers are enumerated in order
0009 which usually means the lowest number scsi_host corresponds
0010 with the first controller, but this association is not
0011 guaranteed. The 'isci_id' attribute unambiguously identifies
0012 the controller index: '0' for the first controller,
0013 '1' for the second.
0014
0015 What: /sys/class/scsi_host/hostX/acciopath_status
0016 Date: November 2013
0017 Contact: Stephen M. Cameron <scameron@beardog.cce.hp.com>
0018 Description: This file contains the current status of the "SSD Smart Path"
0019 feature of HP Smart Array RAID controllers using the hpsa
0020 driver. SSD Smart Path, when enabled permits the driver to
0021 send i/o requests directly to physical devices that are part
0022 of a logical drive, bypassing the controllers firmware RAID
0023 stack for a performance advantage when possible. A value of
0024 '1' indicates the feature is enabled, and the controller may
0025 use the direct i/o path to physical devices. A value of zero
0026 means the feature is disabled and the controller may not use
0027 the direct i/o path to physical devices. This setting is
0028 controller wide, affecting all configured logical drives on the
0029 controller. This file is readable and writable.
0030
0031 What: /sys/class/scsi_host/hostX/link_power_management_policy
0032 Date: Oct, 2007
0033 KernelVersion: v2.6.24
0034 Contact: linux-ide@vger.kernel.org
0035 Description:
0036 (RW) This parameter allows the user to read and set the link
0037 (interface) power management.
0038
0039 There are four possible options:
0040
0041 min_power: Tell the controller to try to make the link use the
0042 least possible power when possible. This may sacrifice some
0043 performance due to increased latency when coming out of lower
0044 power states.
0045
0046 max_performance: Generally, this means no power management.
0047 Tell the controller to have performance be a priority over power
0048 management.
0049
0050 medium_power: Tell the controller to enter a lower power state
0051 when possible, but do not enter the lowest power state, thus
0052 improving latency over min_power setting.
0053
0054 med_power_with_dipm: Identical to the existing medium_power
0055 setting except that it enables dipm (device initiated power
0056 management) on top, which makes it match the Windows IRST (Intel
0057 Rapid Storage Technology) driver settings. This setting is also
0058 close to min_power, except that:
0059
0060 a) It does not use host-initiated slumber mode, but it does
0061 allow device-initiated slumber
0062 b) It does not enable low power device sleep mode (DevSlp).
0063
0064 What: /sys/class/scsi_host/hostX/em_message
0065 What: /sys/class/scsi_host/hostX/em_message_type
0066 Date: Jun, 2008
0067 KernelVersion: v2.6.27
0068 Contact: linux-ide@vger.kernel.org
0069 Description:
0070 em_message: (RW) Enclosure management support. For the LED
0071 protocol, writes and reads correspond to the LED message format
0072 as defined in the AHCI spec.
0073
0074 The user must turn sw_activity (under `/sys/block/*/device/`)
0075 OFF it they wish to control the activity LED via the em_message
0076 file.
0077
0078 em_message_type: (RO) Displays the current enclosure management
0079 protocol that is being used by the driver (for eg. LED, SAF-TE,
0080 SES-2, SGPIO etc).
0081
0082 What: /sys/class/scsi_host/hostX/ahci_port_cmd
0083 What: /sys/class/scsi_host/hostX/ahci_host_caps
0084 What: /sys/class/scsi_host/hostX/ahci_host_cap2
0085 Date: Mar, 2010
0086 KernelVersion: v2.6.35
0087 Contact: linux-ide@vger.kernel.org
0088 Description:
0089 [to be documented]
0090
0091 What: /sys/class/scsi_host/hostX/ahci_host_version
0092 Date: Mar, 2010
0093 KernelVersion: v2.6.35
0094 Contact: linux-ide@vger.kernel.org
0095 Description:
0096 (RO) Display the version of the AHCI spec implemented by the
0097 host.
0098
0099 What: /sys/class/scsi_host/hostX/em_buffer
0100 Date: Apr, 2010
0101 KernelVersion: v2.6.35
0102 Contact: linux-ide@vger.kernel.org
0103 Description:
0104 (RW) Allows access to AHCI EM (enclosure management) buffer
0105 directly if the host supports EM.
0106
0107 For eg. the AHCI driver supports SGPIO EM messages but the
0108 SATA/AHCI specs do not define the SGPIO message format of the EM
0109 buffer. Different hardware(HW) vendors may have different
0110 definitions. With the em_buffer attribute, this issue can be
0111 solved by allowing HW vendors to provide userland drivers and
0112 tools for their SGPIO initiators.
0113
0114 What: /sys/class/scsi_host/hostX/em_message_supported
0115 Date: Oct, 2009
0116 KernelVersion: v2.6.39
0117 Contact: linux-ide@vger.kernel.org
0118 Description:
0119 (RO) Displays supported enclosure management message types.
