linux-sg2042/Documentation/ABI
Linus Torvalds 4dc4226f99 ACPI and power management updates for 3.16-rc1
- ACPICA update to upstream version 20140424.  That includes a
    number of fixes and improvements related to things like GPE
    handling, table loading, headers, memory mapping and unmapping,
    DSDT/SSDT overriding, and the Unload() operator.  The acpidump
    utility from upstream ACPICA is included too.  From Bob Moore,
    Lv Zheng, David Box, David Binderman, and Colin Ian King.
 
  - Fixes and cleanups related to ACPI video and backlight interfaces
    from Hans de Goede.  That includes blacklist entries for some new
    machines and using native backlight by default.
 
  - ACPI device enumeration changes to create platform devices
    rather than PNP devices for ACPI device objects with _HID by
    default.  PNP devices will still be created for the ACPI device
    object with device IDs corresponding to real PNP devices, so
    that change should not break things left and right, and we're
    expecting to see more and more ACPI-enumerated platform devices
    in the future.  From Zhang Rui and Rafael J Wysocki.
 
  - Updates for the ACPI LPSS (Low-Power Subsystem) driver allowing
    it to handle system suspend/resume on Asus T100 correctly.
    From Heikki Krogerus and Rafael J Wysocki.
 
  - PM core update introducing a mechanism to allow runtime-suspended
    devices to stay suspended over system suspend/resume transitions
    if certain additional conditions related to coordination within
    device hierarchy are met.  Related PM documentation update and
    ACPI PM domain support for the new feature.  From Rafael J Wysocki.
 
  - Fixes and improvements related to the "freeze" sleep state. They
    affect several places including cpuidle, PM core, ACPI core, and
    the ACPI battery driver.  From Rafael J Wysocki and Zhang Rui.
 
  - Miscellaneous fixes and updates of the ACPI core from Aaron Lu,
    Bjørn Mork, Hanjun Guo, Lan Tianyu, and Rafael J Wysocki.
 
  - Fixes and cleanups for the ACPI processor and ACPI PAD (Processor
    Aggregator Device) drivers from Baoquan He, Manuel Schölling,
    Tony Camuso, and Toshi Kani.
 
  - System suspend/resume optimization in the ACPI battery driver from
    Lan Tianyu.
 
  - OPP (Operating Performance Points) subsystem updates from
    Chander Kashyap, Mark Brown, and Nishanth Menon.
 
  - cpufreq core fixes, updates and cleanups from Srivatsa S Bhat,
    Stratos Karafotis, and Viresh Kumar.
 
  - Updates, fixes and cleanups for the Tegra, powernow-k8, imx6q,
    s5pv210, nforce2, and powernv cpufreq drivers from Brian Norris,
    Jingoo Han, Paul Bolle, Philipp Zabel, Stratos Karafotis, and
    Viresh Kumar.
 
  - intel_pstate driver fixes and cleanups from Dirk Brandewie,
    Doug Smythies, and Stratos Karafotis.
 
  - Enabling the big.LITTLE cpufreq driver on arm64 from Mark Brown.
 
  - Fix for the cpuidle menu governor from Chander Kashyap.
 
  - New ARM clps711x cpuidle driver from Alexander Shiyan.
 
  - Hibernate core fixes and cleanups from Chen Gang, Dan Carpenter,
    Fabian Frederick, Pali Rohár, and Sebastian Capella.
 
  - Intel RAPL (Running Average Power Limit) driver updates from
    Jacob Pan.
 
  - PNP subsystem updates from Bjorn Helgaas and Fabian Frederick.
 
  - devfreq core updates from Chanwoo Choi and Paul Bolle.
 
  - devfreq updates for exynos4 and exynos5 from Chanwoo Choi and
    Bartlomiej Zolnierkiewicz.
 
  - turbostat tool fix from Jean Delvare.
 
  - cpupower tool updates from Prarit Bhargava, Ramkumar Ramachandra
    and Thomas Renninger.
 
  - New ACPI ec_access.c tool for poking at the EC in a safe way
    from Thomas Renninger.
 
 /
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.22 (GNU/Linux)
 
 iQIcBAABCAAGBQJTjl16AAoJEILEb/54YlRxeKgP/RRQSV7lFtf582Dw/5M/iWOg
 qYeNtuYFLArEmJ7SpxHdKsU1ZRm3CahAS1j7grvQMQasUxTzoavMcSBNZefeaoNK
 d01LVNqcyKCZs3+izRezk5N1IY+AjdrOcqCdIk8rfgFnc6kOttYUrVcIzKuIKAvJ
 MsJ5s/uqP8G69FsAA3Ttdtr0HKiQhN4skSt424wntQRDeJNZPBs74mPKBGh8bxlO
 Zr/VCDibKQ2Z8jS7x+TzwZrOxgE1/9x0Cub6GAdTvAfS8A+utPwSkneUyopNqpQ+
 tJ5rz5R+HpmPMerizBuU+5s+tvjDPtH4/OZvOPSpYraQSFLOwx3hAm+a5k7fOGmc
 XWjXnXWT0i0V3iQkwrspTNjX1RgywbsHbmXrcWn192HResvMQ9zk2gH2ch6m8JhN
 yTV5V51dOZicpPuaTCvIkJpsV33p6vRz+EdPBiXoEdua5KKtOg8EnQ470dNaMR92
 3ZtWmIvSgGlyPyHlSHLfGXbPUwTYvDNV3aheIoXp9E6WY3WJN9J3WXm4EHKBNVaI
 H83kwuk1s92cgqh22H5Pcb0CmDcrbkUdP6hhsPS/aL80/EJMljRP2AYW1Y+l1LAf
 pzMLmekHFqQEDjFQltwGvFV/EjFeMHnqOgQONx9ygMaayCGGTYSDx3FbRDesf8t9
 qhoFcTPSxoo0XjrGrR6b
 =tpdF
 -----END PGP SIGNATURE-----

Merge tag 'pm+acpi-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm into next

Pull ACPI and power management updates from Rafael Wysocki:
 "ACPICA is the leader this time (63 commits), followed by cpufreq (28
  commits), devfreq (15 commits), system suspend/hibernation (12
  commits), ACPI video and ACPI device enumeration (10 commits each).

  We have no major new features this time, but there are a few
  significant changes of how things work.  The most visible one will
  probably be that we are now going to create platform devices rather
  than PNP devices by default for ACPI device objects with _HID.  That
  was long overdue and will be really necessary to be able to use the
  same drivers for the same hardware blocks on ACPI and DT-based systems
  going forward.  We're not expecting fallout from this one (as usual),
  but it's something to watch nevertheless.

  The second change having a chance to be visible is that ACPI video
  will now default to using native backlight rather than the ACPI
  backlight interface which should generally help systems with broken
  Win8 BIOSes.  We're hoping that all problems with the native backlight
  handling that we had previously have been addressed and we are in a
  good enough shape to flip the default, but this change should be easy
  enough to revert if need be.

  In addition to that, the system suspend core has a new mechanism to
  allow runtime-suspended devices to stay suspended throughout system
  suspend/resume transitions if some extra conditions are met
  (generally, they are related to coordination within device hierarchy).
  However, enabling this feature requires cooperation from the bus type
  layer and for now it has only been implemented for the ACPI PM domain
  (used by ACPI-enumerated platform devices mostly today).

  Also, the acpidump utility that was previously shipped as a separate
  tool will now be provided by the upstream ACPICA along with the rest
  of ACPICA code, which will allow it to be more up to date and better
  supported, and we have one new cpuidle driver (ARM clps711x).

  The rest is improvements related to certain specific use cases,
  cleanups and fixes all over the place.

  Specifics:

   - ACPICA update to upstream version 20140424.  That includes a number
     of fixes and improvements related to things like GPE handling,
     table loading, headers, memory mapping and unmapping, DSDT/SSDT
     overriding, and the Unload() operator.  The acpidump utility from
     upstream ACPICA is included too.  From Bob Moore, Lv Zheng, David
     Box, David Binderman, and Colin Ian King.

   - Fixes and cleanups related to ACPI video and backlight interfaces
     from Hans de Goede.  That includes blacklist entries for some new
     machines and using native backlight by default.

   - ACPI device enumeration changes to create platform devices rather
     than PNP devices for ACPI device objects with _HID by default.  PNP
     devices will still be created for the ACPI device object with
     device IDs corresponding to real PNP devices, so that change should
     not break things left and right, and we're expecting to see more
     and more ACPI-enumerated platform devices in the future.  From
     Zhang Rui and Rafael J Wysocki.

   - Updates for the ACPI LPSS (Low-Power Subsystem) driver allowing it
     to handle system suspend/resume on Asus T100 correctly.  From
     Heikki Krogerus and Rafael J Wysocki.

   - PM core update introducing a mechanism to allow runtime-suspended
     devices to stay suspended over system suspend/resume transitions if
     certain additional conditions related to coordination within device
     hierarchy are met.  Related PM documentation update and ACPI PM
     domain support for the new feature.  From Rafael J Wysocki.

   - Fixes and improvements related to the "freeze" sleep state.  They
     affect several places including cpuidle, PM core, ACPI core, and
     the ACPI battery driver.  From Rafael J Wysocki and Zhang Rui.

   - Miscellaneous fixes and updates of the ACPI core from Aaron Lu,
     Bjørn Mork, Hanjun Guo, Lan Tianyu, and Rafael J Wysocki.

   - Fixes and cleanups for the ACPI processor and ACPI PAD (Processor
     Aggregator Device) drivers from Baoquan He, Manuel Schölling, Tony
     Camuso, and Toshi Kani.

   - System suspend/resume optimization in the ACPI battery driver from
     Lan Tianyu.

   - OPP (Operating Performance Points) subsystem updates from Chander
     Kashyap, Mark Brown, and Nishanth Menon.

   - cpufreq core fixes, updates and cleanups from Srivatsa S Bhat,
     Stratos Karafotis, and Viresh Kumar.

   - Updates, fixes and cleanups for the Tegra, powernow-k8, imx6q,
     s5pv210, nforce2, and powernv cpufreq drivers from Brian Norris,
     Jingoo Han, Paul Bolle, Philipp Zabel, Stratos Karafotis, and
     Viresh Kumar.

   - intel_pstate driver fixes and cleanups from Dirk Brandewie, Doug
     Smythies, and Stratos Karafotis.

   - Enabling the big.LITTLE cpufreq driver on arm64 from Mark Brown.

   - Fix for the cpuidle menu governor from Chander Kashyap.

   - New ARM clps711x cpuidle driver from Alexander Shiyan.

   - Hibernate core fixes and cleanups from Chen Gang, Dan Carpenter,
     Fabian Frederick, Pali Rohár, and Sebastian Capella.

   - Intel RAPL (Running Average Power Limit) driver updates from Jacob
     Pan.

   - PNP subsystem updates from Bjorn Helgaas and Fabian Frederick.

   - devfreq core updates from Chanwoo Choi and Paul Bolle.

   - devfreq updates for exynos4 and exynos5 from Chanwoo Choi and
     Bartlomiej Zolnierkiewicz.

   - turbostat tool fix from Jean Delvare.

   - cpupower tool updates from Prarit Bhargava, Ramkumar Ramachandra
     and Thomas Renninger.

   - New ACPI ec_access.c tool for poking at the EC in a safe way from
     Thomas Renninger"

* tag 'pm+acpi-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (187 commits)
  ACPICA: Namespace: Remove _PRP method support.
  intel_pstate: Improve initial busy calculation
  intel_pstate: add sample time scaling
  intel_pstate: Correct rounding in busy calculation
  intel_pstate: Remove C0 tracking
  PM / hibernate: fixed typo in comment
  ACPI: Fix x86 regression related to early mapping size limitation
  ACPICA: Tables: Add mechanism to control early table checksum verification.
  ACPI / scan: use platform bus type by default for _HID enumeration
  ACPI / scan: always register ACPI LPSS scan handler
  ACPI / scan: always register memory hotplug scan handler
  ACPI / scan: always register container scan handler
  ACPI / scan: Change the meaning of missing .attach() in scan handlers
  ACPI / scan: introduce platform_id device PNP type flag
  ACPI / scan: drop unsupported serial IDs from PNP ACPI scan handler ID list
  ACPI / scan: drop IDs that do not comply with the ACPI PNP ID rule
  ACPI / PNP: use device ID list for PNPACPI device enumeration
  ACPI / scan: .match() callback for ACPI scan handlers
  ACPI / battery: wakeup the system only when necessary
  power_supply: allow power supply devices registered w/o wakeup source
  ...
2014-06-04 08:57:16 -07:00
..
obsolete Merge branches 'for-3.7/upstream-fixes', 'for-3.8/hidraw', 'for-3.8/i2c-hid', 'for-3.8/multitouch', 'for-3.8/roccat', 'for-3.8/sensors' and 'for-3.8/upstream' into for-linus 2012-12-12 21:41:55 +01:00
removed netfilter: remove ip_queue support 2012-05-08 20:25:42 +02:00
stable powerpc/powernv Platform dump interface 2014-03-07 16:19:10 +11:00
testing ACPI and power management updates for 3.16-rc1 2014-06-04 08:57:16 -07:00
README Documentation/ABI: document the non-ABI status of Kconfig and symbols 2013-11-13 12:09:32 +09:00

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/stable_api_nonsense.txt.