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