blob: 17f2bc7dd261c45ecb43087bf35e46665c9592a1 [file] [log] [blame]
What: /sys/block/*/device/sw_activity
Date: Jun, 2008
KernelVersion: v2.6.27
(RW) Used by drivers which support software controlled activity
It has the following valid values:
0 OFF - the LED is not activated on activity
1 BLINK_ON - the LED blinks on every 10ms when activity is
2 BLINK_OFF - the LED is on when idle, and blinks off
every 10ms when activity is detected.
Note that the user must turn sw_activity OFF it they wish to
control the activity LED via the em_message file.
What: /sys/block/*/device/unload_heads
Date: Sep, 2008
KernelVersion: v2.6.28
(RW) Hard disk shock protection
Writing an integer value to this file will take the heads of the
respective drive off the platter and block all I/O operations
for the specified number of milliseconds.
- If the device does not support the unload heads feature,
access is denied with -EOPNOTSUPP.
- The maximal value accepted for a timeout is 30000
- A previously set timeout can be cancelled and disk can resume
normal operation immediately by specifying a timeout of 0.
- Some hard drives only comply with an earlier version of the
ATA standard, but support the unload feature nonetheless.
There is no safe way Linux can detect these devices, so this
is not enabled by default. If it is known that your device
does support the unload feature, then you can tell the kernel
to enable it by writing -1. It can be disabled again by
writing -2.
- Values below -2 are rejected with -EINVAL
For more information, see
What: /sys/block/*/device/ncq_prio_enable
Date: Oct, 2016
KernelVersion: v4.10
(RW) Write to the file to turn on or off the SATA ncq (native
command queueing) support. By default this feature is turned