| What: /sys/class/scsi_host/hostX/isci_id |
| Date: June 2011 |
| Contact: Dave Jiang <dave.jiang@intel.com> |
| Description: |
| This file contains the enumerated host ID for the Intel |
| SCU controller. The Intel(R) C600 Series Chipset SATA/SAS |
| Storage Control Unit embeds up to two 4-port controllers in |
| a single PCI device. The controllers are enumerated in order |
| which usually means the lowest number scsi_host corresponds |
| with the first controller, but this association is not |
| guaranteed. The 'isci_id' attribute unambiguously identifies |
| the controller index: '0' for the first controller, |
| '1' for the second. |
| |
| What: /sys/class/scsi_host/hostX/acciopath_status |
| Date: November 2013 |
| Contact: Stephen M. Cameron <scameron@beardog.cce.hp.com> |
| Description: This file contains the current status of the "SSD Smart Path" |
| feature of HP Smart Array RAID controllers using the hpsa |
| driver. SSD Smart Path, when enabled permits the driver to |
| send i/o requests directly to physical devices that are part |
| of a logical drive, bypassing the controllers firmware RAID |
| stack for a performance advantage when possible. A value of |
| '1' indicates the feature is enabled, and the controller may |
| use the direct i/o path to physical devices. A value of zero |
| means the feature is disabled and the controller may not use |
| the direct i/o path to physical devices. This setting is |
| controller wide, affecting all configured logical drives on the |
| controller. This file is readable and writable. |
| |
| What: /sys/class/scsi_host/hostX/link_power_management_policy |
| Date: Oct, 2007 |
| KernelVersion: v2.6.24 |
| Contact: linux-ide@vger.kernel.org |
| Description: |
| (RW) This parameter allows the user to read and set the link |
| (interface) power management. |
| |
| There are four possible options: |
| |
| min_power: Tell the controller to try to make the link use the |
| least possible power when possible. This may sacrifice some |
| performance due to increased latency when coming out of lower |
| power states. |
| |
| max_performance: Generally, this means no power management. |
| Tell the controller to have performance be a priority over power |
| management. |
| |
| medium_power: Tell the controller to enter a lower power state |
| when possible, but do not enter the lowest power state, thus |
| improving latency over min_power setting. |
| |
| med_power_with_dipm: Identical to the existing medium_power |
| setting except that it enables dipm (device initiated power |
| management) on top, which makes it match the Windows IRST (Intel |
| Rapid Storage Technology) driver settings. This setting is also |
| close to min_power, except that: |
| |
| a) It does not use host-initiated slumber mode, but it does |
| allow device-initiated slumber |
| b) It does not enable low power device sleep mode (DevSlp). |
| |
| What: /sys/class/scsi_host/hostX/em_message |
| What: /sys/class/scsi_host/hostX/em_message_type |
| Date: Jun, 2008 |
| KernelVersion: v2.6.27 |
| Contact: linux-ide@vger.kernel.org |
| Description: |
| em_message: (RW) Enclosure management support. For the LED |
| protocol, writes and reads correspond to the LED message format |
| as defined in the AHCI spec. |
| |
| The user must turn sw_activity (under `/sys/block/*/device/`) |
| OFF it they wish to control the activity LED via the em_message |
| file. |
| |
| em_message_type: (RO) Displays the current enclosure management |
| protocol that is being used by the driver (for eg. LED, SAF-TE, |
| SES-2, SGPIO etc). |
| |
| What: /sys/class/scsi_host/hostX/ahci_port_cmd |
| What: /sys/class/scsi_host/hostX/ahci_host_caps |
| What: /sys/class/scsi_host/hostX/ahci_host_cap2 |
| Date: Mar, 2010 |
| KernelVersion: v2.6.35 |
| Contact: linux-ide@vger.kernel.org |
| Description: |
| [to be documented] |
| |
| What: /sys/class/scsi_host/hostX/ahci_host_version |
| Date: Mar, 2010 |
| KernelVersion: v2.6.35 |
| Contact: linux-ide@vger.kernel.org |
| Description: |
| (RO) Display the version of the AHCI spec implemented by the |
| host. |
| |
| What: /sys/class/scsi_host/hostX/em_buffer |
| Date: Apr, 2010 |
| KernelVersion: v2.6.35 |
| Contact: linux-ide@vger.kernel.org |
| Description: |
| (RW) Allows access to AHCI EM (enclosure management) buffer |
| directly if the host supports EM. |
| |
| For eg. the AHCI driver supports SGPIO EM messages but the |
| SATA/AHCI specs do not define the SGPIO message format of the EM |
| buffer. Different hardware(HW) vendors may have different |
| definitions. With the em_buffer attribute, this issue can be |
| solved by allowing HW vendors to provide userland drivers and |
| tools for their SGPIO initiators. |
| |
| What: /sys/class/scsi_host/hostX/em_message_supported |
| Date: Oct, 2009 |
| KernelVersion: v2.6.39 |
| Contact: linux-ide@vger.kernel.org |
| Description: |
| (RO) Displays supported enclosure management message types. |
