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Diffstat (limited to 'Documentation/ABI/testing/sysfs-block-device')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-block-device | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-device b/Documentation/ABI/testing/sysfs-block-device new file mode 100644 index 000000000..aa0fb500e --- /dev/null +++ b/Documentation/ABI/testing/sysfs-block-device @@ -0,0 +1,60 @@ +What: /sys/block/*/device/sw_activity +Date: Jun, 2008 +KernelVersion: v2.6.27 +Contact: linux-ide@vger.kernel.org +Description: + (RW) Used by drivers which support software controlled activity + LEDs. + + 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 + detected. + 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 +Contact: linux-ide@vger.kernel.org +Description: + (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 + milliseconds. + - 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 + Documentation/admin-guide/laptops/disk-shock-protection.rst + + +What: /sys/block/*/device/ncq_prio_enable +Date: Oct, 2016 +KernelVersion: v4.10 +Contact: linux-ide@vger.kernel.org +Description: + (RW) Write to the file to turn on or off the SATA ncq (native + command queueing) support. By default this feature is turned + off. |