| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | What: /sys/block/*/device/sw_activity |
| 2 | Date: Jun, 2008 |
| 3 | KernelVersion: v2.6.27 |
| 4 | Contact: linux-ide@vger.kernel.org |
| 5 | Description: |
| 6 | (RW) Used by drivers which support software controlled activity |
| 7 | LEDs. |
| 8 | |
| 9 | It has the following valid values: |
| 10 | |
| 11 | 0 OFF - the LED is not activated on activity |
| 12 | 1 BLINK_ON - the LED blinks on every 10ms when activity is |
| 13 | detected. |
| 14 | 2 BLINK_OFF - the LED is on when idle, and blinks off |
| 15 | every 10ms when activity is detected. |
| 16 | |
| 17 | Note that the user must turn sw_activity OFF it they wish to |
| 18 | control the activity LED via the em_message file. |
| 19 | |
| 20 | |
| 21 | What: /sys/block/*/device/unload_heads |
| 22 | Date: Sep, 2008 |
| 23 | KernelVersion: v2.6.28 |
| 24 | Contact: linux-ide@vger.kernel.org |
| 25 | Description: |
| 26 | (RW) Hard disk shock protection |
| 27 | |
| 28 | Writing an integer value to this file will take the heads of the |
| 29 | respective drive off the platter and block all I/O operations |
| 30 | for the specified number of milliseconds. |
| 31 | |
| 32 | - If the device does not support the unload heads feature, |
| 33 | access is denied with -EOPNOTSUPP. |
| 34 | - The maximal value accepted for a timeout is 30000 |
| 35 | milliseconds. |
| 36 | - A previously set timeout can be cancelled and disk can resume |
| 37 | normal operation immediately by specifying a timeout of 0. |
| 38 | - Some hard drives only comply with an earlier version of the |
| 39 | ATA standard, but support the unload feature nonetheless. |
| 40 | There is no safe way Linux can detect these devices, so this |
| 41 | is not enabled by default. If it is known that your device |
| 42 | does support the unload feature, then you can tell the kernel |
| 43 | to enable it by writing -1. It can be disabled again by |
| 44 | writing -2. |
| 45 | - Values below -2 are rejected with -EINVAL |
| 46 | |
| 47 | For more information, see |
| 48 | Documentation/admin-guide/laptops/disk-shock-protection.rst |
| 49 | |
| 50 | |
| 51 | What: /sys/block/*/device/ncq_prio_enable |
| 52 | Date: Oct, 2016 |
| 53 | KernelVersion: v4.10 |
| 54 | Contact: linux-ide@vger.kernel.org |
| 55 | Description: |
| 56 | (RW) Write to the file to turn on or off the SATA ncq (native |
| 57 | command queueing) support. By default this feature is turned |
| 58 | off. |