1What: /sys/block/*/device/sw_activity 2Date: Jun, 2008 3KernelVersion: v2.6.27 4Contact: linux-ide@vger.kernel.org 5Description: 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 23What: /sys/block/*/device/unload_heads 24Date: Sep, 2008 25KernelVersion: v2.6.28 26Contact: linux-ide@vger.kernel.org 27Description: 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 53What: /sys/block/*/device/ncq_prio_enable 54Date: Oct, 2016 55KernelVersion: v4.10 56Contact: linux-ide@vger.kernel.org 57Description: 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 65What: /sys/block/*/device/sas_ncq_prio_enable 66Date: Oct, 2016 67KernelVersion: v4.10 68Contact: linux-ide@vger.kernel.org 69Description: 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 78What: /sys/block/*/device/ncq_prio_supported 79Date: Aug, 2021 80KernelVersion: v5.15 81Contact: linux-ide@vger.kernel.org 82Description: 83 (RO) Indicates if the device supports the SATA NCQ (native 84 command queueing) priority feature. 85 86 87What: /sys/block/*/device/sas_ncq_prio_supported 88Date: Aug, 2021 89KernelVersion: v5.15 90Contact: linux-ide@vger.kernel.org 91Description: 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 100What: /sys/block/*/device/cdl_supported 101Date: May, 2023 102KernelVersion: v6.5 103Contact: linux-scsi@vger.kernel.org 104Description: 105 (RO) Indicates if the device supports the command duration 106 limits feature found in some ATA and SCSI devices. 107 108 109What: /sys/block/*/device/cdl_enable 110Date: May, 2023 111KernelVersion: v6.5 112Contact: linux-scsi@vger.kernel.org 113Description: 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. 120