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) support. By default this feature is turned
60		off.
61