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.