| What: /sys/block/*/device/sw_activity | |
| Date: Jun, 2008 | |
| KernelVersion: v2.6.27 | |
| Contact: linux-ide@vger.kernel.org | |
| Description: | |
| (RW) Used by drivers which support software controlled activity | |
| LEDs. | |
| It has the following valid values: | |
| == ======================================================== | |
| 0 OFF - the LED is not activated on activity | |
| 1 BLINK_ON - the LED blinks on every 10ms when activity is | |
| detected. | |
| 2 BLINK_OFF - the LED is on when idle, and blinks off | |
| every 10ms when activity is detected. | |
| == ======================================================== | |
| Note that the user must turn sw_activity OFF it they wish to | |
| control the activity LED via the em_message file. | |
| What: /sys/block/*/device/unload_heads | |
| Date: Sep, 2008 | |
| KernelVersion: v2.6.28 | |
| Contact: linux-ide@vger.kernel.org | |
| Description: | |
| (RW) Hard disk shock protection | |
| Writing an integer value to this file will take the heads of the | |
| respective drive off the platter and block all I/O operations | |
| for the specified number of milliseconds. | |
| - If the device does not support the unload heads feature, | |
| access is denied with -EOPNOTSUPP. | |
| - The maximal value accepted for a timeout is 30000 | |
| milliseconds. | |
| - A previously set timeout can be cancelled and disk can resume | |
| normal operation immediately by specifying a timeout of 0. | |
| - Some hard drives only comply with an earlier version of the | |
| ATA standard, but support the unload feature nonetheless. | |
| There is no safe way Linux can detect these devices, so this | |
| is not enabled by default. If it is known that your device | |
| does support the unload feature, then you can tell the kernel | |
| to enable it by writing -1. It can be disabled again by | |
| writing -2. | |
| - Values below -2 are rejected with -EINVAL | |
| For more information, see | |
| Documentation/admin-guide/laptops/disk-shock-protection.rst | |
| What: /sys/block/*/device/ncq_prio_enable | |
| Date: Oct, 2016 | |
| KernelVersion: v4.10 | |
| Contact: linux-ide@vger.kernel.org | |
| Description: | |
| (RW) Write to the file to turn on or off the SATA NCQ (native | |
| command queueing) priority support. By default this feature is | |
| turned off. If the device does not support the SATA NCQ | |
| priority feature, writing "1" to this file results in an error | |
| (see ncq_prio_supported). | |
| What: /sys/block/*/device/sas_ncq_prio_enable | |
| Date: Oct, 2016 | |
| KernelVersion: v4.10 | |
| Contact: linux-ide@vger.kernel.org | |
| Description: | |
| (RW) This is the equivalent of the ncq_prio_enable attribute | |
| file for SATA devices connected to a SAS host-bus-adapter | |
| (HBA) implementing support for the SATA NCQ priority feature. | |
| This file does not exist if the HBA driver does not implement | |
| support for the SATA NCQ priority feature, regardless of the | |
| device support for this feature (see sas_ncq_prio_supported). | |
| What: /sys/block/*/device/ncq_prio_supported | |
| Date: Aug, 2021 | |
| KernelVersion: v5.15 | |
| Contact: linux-ide@vger.kernel.org | |
| Description: | |
| (RO) Indicates if the device supports the SATA NCQ (native | |
| command queueing) priority feature. | |
| What: /sys/block/*/device/sas_ncq_prio_supported | |
| Date: Aug, 2021 | |
| KernelVersion: v5.15 | |
| Contact: linux-ide@vger.kernel.org | |
| Description: | |
| (RO) This is the equivalent of the ncq_prio_supported attribute | |
| file for SATA devices connected to a SAS host-bus-adapter | |
| (HBA) implementing support for the SATA NCQ priority feature. | |
| This file does not exist if the HBA driver does not implement | |
| support for the SATA NCQ priority feature, regardless of the | |
| device support for this feature. | |
| What: /sys/block/*/device/cdl_supported | |
| Date: May, 2023 | |
| KernelVersion: v6.5 | |
| Contact: linux-scsi@vger.kernel.org | |
| Description: | |
| (RO) Indicates if the device supports the command duration | |
| limits feature found in some ATA and SCSI devices. | |
| What: /sys/block/*/device/cdl_enable | |
| Date: May, 2023 | |
| KernelVersion: v6.5 | |
| Contact: linux-scsi@vger.kernel.org | |
| Description: | |
| (RW) For a device supporting the command duration limits | |
| feature, write to the file to turn on or off the feature. | |
| By default this feature is turned off. | |
| Writing "1" to this file enables the use of command duration | |
| limits for read and write commands in the kernel and turns on | |
| the feature on the device. Writing "0" disables the feature. |