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Commit 4f1c29d0 authored by Aishwarya Pant's avatar Aishwarya Pant Committed by Rafael J. Wysocki
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ACPI: sysfs: Update device object sysfs documentation 



Add documentation for two attributes, status and hrv, in
Documentation/ABI/testing/sysfs-bus-acpi.

Compiled from git logs and the ACPI specification.

Signed-off-by: default avatarAishwarya Pant <aishpant@gmail.com>
[ rjw: Minor changes ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 91ab883e

Documentation/ABI/testing/sysfs-bus-acpi

+37 −0
Original line number Diff line number Diff line
@@ -56,3 +56,40 @@ Description: 
		Writing 1 to this attribute will trigger hot removal of

		this device object.  This file exists for every device

		object that has _EJ0 method.



What:		/sys/bus/acpi/devices/.../status

Date:		Jan, 2014

Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>

Description:

		(RO) Returns the ACPI device status: enabled, disabled or

		functioning or present, if the method _STA is present.



		The return value is a decimal integer representing the device's

		status bitmap:



		Bit [0] –  Set if the device is present.

		Bit [1] –  Set if the device is enabled and decoding its

		           resources.

		Bit [2] –  Set if the device should be shown in the UI.

		Bit [3] –  Set if the device is functioning properly (cleared if

		           device failed its diagnostics).

		Bit [4] –  Set if the battery is present.

		Bits [31:5] –  Reserved (must be cleared)



		If bit [0] is clear, then bit 1 must also be clear (a device

		that is not present cannot be enabled).



		Bit 0 can be clear (not present) with bit [3] set (device is

		functional).  This case is used to indicate a valid device for

		which no device driver should be loaded.



		More special cases are covered in the ACPI specification.



What:		/sys/bus/acpi/devices/.../hrv

Date:		Apr, 2016

Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>

Description:

		(RO) Allows users to read the hardware version of non-PCI

		hardware, if the _HRV control method is present.  It is mostly

		useful for non-PCI devices because lspci can list the hardware

		version for PCI devices.