| 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) support. By default this feature is turned |
| off. |