linux/Documentation/ABI
Linus Torvalds 08be881064 ACPI updates for v4.12-rc1
- Update the core device enumeration code to make it more internally
    consistent and robust and drop the force_remove sysfs attribute
    that could be used to tell it to ignore errors on device
    hot-removal which was dangerous in general and no real and
    still relevant use cases for it could be found (Rafael Wysocki,
    Michal Hocko).
 
  - Make the core device enumeration code use _PXM to associate
    platform devices created by it with specific NUMA nodes (Shanker
    Donthineni).
 
  - Extend the CPPC library by adding more sysfs entries for
    performance capabilities to it and making it use the lowest
    nonlinear performance parameter (Prashanth Prakash).
 
  - Make the CPU online more consistent with CPU initialization in
    the ACPI processor driver (Prashanth Prakash).
 
  - Update the AC and battery drivers to help them avoid attaching to
    devices that cannot be handled by them and update the axp288_charger
    power supply driver to work correctly on ACPI systems without the
    INT3496 device (Hans de Goede).
 
  - Add an ACPI operation region driver for the Intel CHT Whiskey Cove
    PMIC and update the xpower operation region driver to work without
    IIO which isn't really necessary for it to work (Hans de Goede).
 
  - Add a new entry for Dell Inspiron 7537 to the _REV quirk blacklist
    (Kai Heng Feng).
 
  - Make the code in the ACPI video driver easier to follow by adding
    symbols and comments to it (Dmitry Frank).
 
  - Update ACPI documentation and drop a function that has no users
    from the tables-handling code (Cao jin, Baoquan He).
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2
 
 iQIcBAABCAAGBQJZB5h0AAoJEILEb/54YlRx8+EP/j468sN7PEBDXZLF1jsIJK6g
 IozbOMAAVXBwDrfTOLYSVe3KOUJH0tVdax768tv6Gu94jbUT+nPeSNNDTaWbOpli
 fi/f6ljSupWzh/TLjIBVAbNuEULcxB6AcMg0fxMRutIQUbr7ie6ioJ1R4UoMRrV8
 HFdlsHiHa9uUMSDuwByzjzQX+TRAvseyBvkLxUlMMwJQ3+/+yH2FoGRmjzS0ZLAC
 lTyzcAasznrGsqlDoFunNegoBFkgnJv5vJ7fVfujQb5irpX51iog6aNehLRt3GwX
 opRlNjFIYk3XTSTR2QvV/utUrWuPYKJwkCulnlyACoWCmsYGbt115iEWY0YNVV71
 tmHRK/TkbYHSg4H/Tgc4i1bMvWM4GOULq3NaltxfQA31O8s++02zL7HxblA763AP
 4TmofNDTW3pF7GZ5DxtysXCCURdShj7y8ta4K+A0l4g6iCaTHLzFNlEJp2WSL6xo
 LFg/VvAHFnF34OlDobKlm8hB53thHGd0UD0dnY4hwiwpsTwlc/e5pxgIpKEkw1/L
 aO3VxIMtzVG93cno7JM7/6kWy2Qcnk2VqoPFiQPaB60QKfyKjBKCRYVeUVesrHrE
 443MoJS3KmsenPSD7ACpW6yKmGP3p+3CKakdvE3C09XNToq98+3W0lsU5NP9ys94
 m75frKXPSt9EAUqjsJ0Z
 =IwcL
 -----END PGP SIGNATURE-----

Merge tag 'acpi-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI updates from Rafael Wysocki:
 "These are some device enumeration code changes, updates of the AC and
  battery drivers to help them avoid attaching to devices that cannot be
  handled by them, new operation region driver for the Intel CHT Whiskey
  Cove PMIC, new sysfs entries for CPPC performance capabilities, a new
  _REV quirk blacklist entry and a couple of assorted minor fixes and
  cleanups.

  Specifics:

   - Update the core device enumeration code to make it more internally
     consistent and robust and drop the force_remove sysfs attribute
     that could be used to tell it to ignore errors on device
     hot-removal which was dangerous in general and no real and still
     relevant use cases for it could be found (Rafael Wysocki, Michal
     Hocko).

   - Make the core device enumeration code use _PXM to associate
     platform devices created by it with specific NUMA nodes (Shanker
     Donthineni).

   - Extend the CPPC library by adding more sysfs entries for
     performance capabilities to it and making it use the lowest
     nonlinear performance parameter (Prashanth Prakash).

   - Make the CPU online more consistent with CPU initialization in the
     ACPI processor driver (Prashanth Prakash).

   - Update the AC and battery drivers to help them avoid attaching to
     devices that cannot be handled by them and update the
     axp288_charger power supply driver to work correctly on ACPI
     systems without the INT3496 device (Hans de Goede).

   - Add an ACPI operation region driver for the Intel CHT Whiskey Cove
     PMIC and update the xpower operation region driver to work without
     IIO which isn't really necessary for it to work (Hans de Goede).

   - Add a new entry for Dell Inspiron 7537 to the _REV quirk blacklist
     (Kai Heng Feng).

   - Make the code in the ACPI video driver easier to follow by adding
     symbols and comments to it (Dmitry Frank).

   - Update ACPI documentation and drop a function that has no users
     from the tables-handling code (Cao jin, Baoquan He)"

* tag 'acpi-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / PMIC: Stop xpower OPRegion handler relying on IIO
  ACPI / PMIC: Add opregion driver for Intel CHT Whiskey Cove PMIC
  ACPI / scan: Avoid enumerating devices more than once
  ACPI / scan: Apply default enumeration to devices with ACPI drivers
  power: supply: axp288_charger: Only wait for INT3496 device if present
  ACPI / AC: Add a blacklist with PMIC ACPI HIDs with a native charger driver
  ACPI / battery: Add a blacklist with PMIC ACPI HIDs with a native battery driver
  ACPI / battery: Fix acpi_battery_exit on acpi_battery_init_async errors
  ACPI / utils: Add new acpi_dev_present helper
  ACPI / video: add comments about subtle cases
  ACPI / video: get rid of magic numbers and use enum instead
  ACPI / doc: linuxized-acpica.txt: fix typos
  ACPI / blacklist: add _REV quirk for Dell Inspiron 7537
  ACPI / tables: Drop acpi_parse_entries() which is not used
  ACPI / CPPC: add sysfs entries for CPPC perf capabilities
  ACPI / CPPC: Read lowest nonlinear perf in cppc_get_perf_caps()
  ACPI / platform: Update platform device NUMA node based on _PXM method
  ACPI / Processor: Drop setup_max_cpus check from acpi_processor_add()
  ACPI / scan: Drop support for force_remove
2017-05-01 14:13:28 -07:00
..
obsolete ACPI / scan: Drop support for force_remove 2017-04-13 03:51:47 +02:00
removed
stable
testing ACPI updates for v4.12-rc1 2017-05-01 14:13:28 -07:00
README

This directory attempts to document the ABI between the Linux kernel and
userspace, and the relative stability of these interfaces.  Due to the
everchanging nature of Linux, and the differing maturity levels, these
interfaces should be used by userspace programs in different ways.

We have four different levels of ABI stability, as shown by the four
different subdirectories in this location.  Interfaces may change levels
of stability according to the rules described below.

The different levels of stability are:

  stable/
	This directory documents the interfaces that the developer has
	defined to be stable.  Userspace programs are free to use these
	interfaces with no restrictions, and backward compatibility for
	them will be guaranteed for at least 2 years.  Most interfaces
	(like syscalls) are expected to never change and always be
	available.

  testing/
	This directory documents interfaces that are felt to be stable,
	as the main development of this interface has been completed.
	The interface can be changed to add new features, but the
	current interface will not break by doing this, unless grave
	errors or security problems are found in them.  Userspace
	programs can start to rely on these interfaces, but they must be
	aware of changes that can occur before these interfaces move to
	be marked stable.  Programs that use these interfaces are
	strongly encouraged to add their name to the description of
	these interfaces, so that the kernel developers can easily
	notify them if any changes occur (see the description of the
	layout of the files below for details on how to do this.)

  obsolete/
  	This directory documents interfaces that are still remaining in
	the kernel, but are marked to be removed at some later point in
	time.  The description of the interface will document the reason
	why it is obsolete and when it can be expected to be removed.

  removed/
	This directory contains a list of the old interfaces that have
	been removed from the kernel.

Every file in these directories will contain the following information:

What:		Short description of the interface
Date:		Date created
KernelVersion:	Kernel version this feature first showed up in.
Contact:	Primary contact for this interface (may be a mailing list)
Description:	Long description of the interface and how to use it.
Users:		All users of this interface who wish to be notified when
		it changes.  This is very important for interfaces in
		the "testing" stage, so that kernel developers can work
		with userspace developers to ensure that things do not
		break in ways that are unacceptable.  It is also
		important to get feedback for these interfaces to make
		sure they are working in a proper way and do not need to
		be changed further.


How things move between levels:

Interfaces in stable may move to obsolete, as long as the proper
notification is given.

Interfaces may be removed from obsolete and the kernel as long as the
documented amount of time has gone by.

Interfaces in the testing state can move to the stable state when the
developers feel they are finished.  They cannot be removed from the
kernel tree without going through the obsolete state first.

It's up to the developer to place their interfaces in the category they
wish for it to start out in.


Notable bits of non-ABI, which should not under any circumstances be considered
stable:

- Kconfig.  Userspace should not rely on the presence or absence of any
  particular Kconfig symbol, in /proc/config.gz, in the copy of .config
  commonly installed to /boot, or in any invocation of the kernel build
  process.

- Kernel-internal symbols.  Do not rely on the presence, absence, location, or
  type of any kernel symbol, either in System.map files or the kernel binary
  itself.  See Documentation/process/stable-api-nonsense.rst.