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		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
21What:		/sys/block/*/device/unload_heads
22Date:		Sep, 2008
23KernelVersion:	v2.6.28
24Contact:	linux-ide@vger.kernel.org
25Description:
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
51What:		/sys/block/*/device/ncq_prio_enable
52Date:		Oct, 2016
53KernelVersion:	v4.10
54Contact:	linux-ide@vger.kernel.org
55Description:
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.
59