| 1 | What: /sys/block/*/device/sw_activity |
| 2 | Date: Jun, 2008 |
| 3 | KernelVersion: v2.6.27 |
| 4 | Contact: [email protected] |
| 5 | Description: |
| 6 | (RW) Used by drivers which support software controlled activity |
| 7 | LEDs. |
| 8 | |
| 9 | It has the following valid values: |
| 10 | |
| 11 | == ======================================================== |
| 12 | 0 OFF - the LED is not activated on activity |
| 13 | 1 BLINK_ON - the LED blinks on every 10ms when activity is |
| 14 | detected. |
| 15 | 2 BLINK_OFF - the LED is on when idle, and blinks off |
| 16 | every 10ms when activity is detected. |
| 17 | == ======================================================== |
| 18 | |
| 19 | Note that the user must turn sw_activity OFF it they wish to |
| 20 | control the activity LED via the em_message file. |
| 21 | |
| 22 | |
| 23 | What: /sys/block/*/device/unload_heads |
| 24 | Date: Sep, 2008 |
| 25 | KernelVersion: v2.6.28 |
| 26 | Contact: [email protected] |
| 27 | Description: |
| 28 | (RW) Hard disk shock protection |
| 29 | |
| 30 | Writing an integer value to this file will take the heads of the |
| 31 | respective drive off the platter and block all I/O operations |
| 32 | for the specified number of milliseconds. |
| 33 | |
| 34 | - If the device does not support the unload heads feature, |
| 35 | access is denied with -EOPNOTSUPP. |
| 36 | - The maximal value accepted for a timeout is 30000 |
| 37 | milliseconds. |
| 38 | - A previously set timeout can be cancelled and disk can resume |
| 39 | normal operation immediately by specifying a timeout of 0. |
| 40 | - Some hard drives only comply with an earlier version of the |
| 41 | ATA standard, but support the unload feature nonetheless. |
| 42 | There is no safe way Linux can detect these devices, so this |
| 43 | is not enabled by default. If it is known that your device |
| 44 | does support the unload feature, then you can tell the kernel |
| 45 | to enable it by writing -1. It can be disabled again by |
| 46 | writing -2. |
| 47 | - Values below -2 are rejected with -EINVAL |
| 48 | |
| 49 | For more information, see |
| 50 | Documentation/admin-guide/laptops/disk-shock-protection.rst |
| 51 | |
| 52 | |
| 53 | What: /sys/block/*/device/ncq_prio_enable |
| 54 | Date: Oct, 2016 |
| 55 | KernelVersion: v4.10 |
| 56 | Contact: [email protected] |
| 57 | Description: |
| 58 | (RW) Write to the file to turn on or off the SATA NCQ (native |
| 59 | command queueing) priority support. By default this feature is |
| 60 | turned off. If the device does not support the SATA NCQ |
| 61 | priority feature, writing "1" to this file results in an error |
| 62 | (see ncq_prio_supported). |
| 63 | |
| 64 | |
| 65 | What: /sys/block/*/device/sas_ncq_prio_enable |
| 66 | Date: Oct, 2016 |
| 67 | KernelVersion: v4.10 |
| 68 | Contact: [email protected] |
| 69 | Description: |
| 70 | (RW) This is the equivalent of the ncq_prio_enable attribute |
| 71 | file for SATA devices connected to a SAS host-bus-adapter |
| 72 | (HBA) implementing support for the SATA NCQ priority feature. |
| 73 | This file does not exist if the HBA driver does not implement |
| 74 | support for the SATA NCQ priority feature, regardless of the |
| 75 | device support for this feature (see sas_ncq_prio_supported). |
| 76 | |
| 77 | |
| 78 | What: /sys/block/*/device/ncq_prio_supported |
| 79 | Date: Aug, 2021 |
| 80 | KernelVersion: v5.15 |
| 81 | Contact: [email protected] |
| 82 | Description: |
| 83 | (RO) Indicates if the device supports the SATA NCQ (native |
| 84 | command queueing) priority feature. |
| 85 | |
| 86 | |
| 87 | What: /sys/block/*/device/sas_ncq_prio_supported |
| 88 | Date: Aug, 2021 |
| 89 | KernelVersion: v5.15 |
| 90 | Contact: [email protected] |
| 91 | Description: |
| 92 | (RO) This is the equivalent of the ncq_prio_supported attribute |
| 93 | file for SATA devices connected to a SAS host-bus-adapter |
| 94 | (HBA) implementing support for the SATA NCQ priority feature. |
| 95 | This file does not exist if the HBA driver does not implement |
| 96 | support for the SATA NCQ priority feature, regardless of the |
| 97 | device support for this feature. |
| 98 | |
| 99 | |
| 100 | What: /sys/block/*/device/cdl_supported |
| 101 | Date: May, 2023 |
| 102 | KernelVersion: v6.5 |
| 103 | Contact: [email protected] |
| 104 | Description: |
| 105 | (RO) Indicates if the device supports the command duration |
| 106 | limits feature found in some ATA and SCSI devices. |
| 107 | |
| 108 | |
| 109 | What: /sys/block/*/device/cdl_enable |
| 110 | Date: May, 2023 |
| 111 | KernelVersion: v6.5 |
| 112 | Contact: [email protected] |
| 113 | Description: |
| 114 | (RW) For a device supporting the command duration limits |
| 115 | feature, write to the file to turn on or off the feature. |
| 116 | By default this feature is turned off. |
| 117 | Writing "1" to this file enables the use of command duration |
| 118 | limits for read and write commands in the kernel and turns on |
| 119 | the feature on the device. Writing "0" disables the feature. |