linux/Documentation/ABI
Linus Torvalds cbd7b8a76b platform-drivers-x86 for v4.16-1
New model support added for Dell, Ideapad, Acer, Asus, Thinkpad, and GPD
 laptops.  Improvements to the common intel-vbtn driver, including tablet
 mode, rotate, and front button support. Intel CPU support added for
 Cannonlake and platform support for Dollar Cove power button.
 
 Overhaul of the mellanox platform driver, creating a new
 platform/mellanox directory for the newly multi-architecture regmap
 interface.
 
 Significant Intel PMC update with CannonLake support, Coffeelake update,
 CPUID enumeration, module support, new read64 API, refactoring and
 cleanups.
 
 Revert the apple-gmux iGP IO lock, addressing reported issues with
 non-binary drivers, leaving Nvidia binary driver users to comment out
 conflicting code.
 
 Miscellaneous fixes and cleanups.
 
 Previously merged during the 4.15-rc cycle:
 - e20a8e771d platform/x86: dell-laptop: Fix keyboard max lighting for Dell Latitude E6410
 - 9cd5cf3710 platform/x86: asus-wireless: send an EV_SYN/SYN_REPORT between state changes
 - 91c73e8092 platform/x86: dell-wmi: check for kmalloc() errors
 - 9a1a625918 platform/x86: wmi: Call acpi_wmi_init() later
 
 The following is an automated git shortlog grouped by driver:
 
 ACPI / LPIT:
  -  Export lpit_read_residency_count_address()
 
 Input:
  -  add KEY_ROTATE_LOCK_TOGGLE
 
 MAINTAINERS:
  -  Update tree for platform-drivers-x86
 
 x86/cpu:
  -  Add Cannonlake to Intel family
 
 acer-wireless:
  - Add Acer Wireless Radio Control driver
 
 intel_chtdc_ti_pwrbtn:
  - Add support for Dollar Cove TI power button
 
 GPD pocket fan:
  -  Add driver for GPD pocket custom fan controller
  -  Stop work on suspend
  -  Use a min-speed of 2 while charging
  -  Set speed to max on get_temp failure
 
 apple-gmux:
  -  Revert: lock iGP IO to protect from vgaarb changes
 
 alienware-wmi:
  -  lightbar LED support for Dell Inspiron 5675
 
 asus-nb-wmi:
  -  Support ALS on the Zenbook UX430UQ
 
 dell-laptop:
  -  Allocate buffer on heap rather than globally
  -  Add 2-in-1 devices to the DMI whitelist
  -  Filter out spurious keyboard backlight change events
  -  make some local functions static
  -  Use bool in struct quirk_entry for true/false fields
 
 dell-smbios:
  -  Correct notation for filtering
 
 dell-wmi:
  -  Add an event created by Dell Latitude 5495
 
 Kconfig
  - have ACPI_CMPC use depends instead of select for INPUT
 
 ideapad-laptop:
  -  Add Y720-15IKB to no_hw_rfkill
  -  add lenovo RESCUER R720-15IKBN to no_hw_rfkill_list
  -  Use __func__ instead of write_ec_cmd in pr_err
  -  Remove unnecessary else
 
 intel-hid:
  -  add a DMI quirk to support Wacom MobileStudio Pro
 
 intel-vbtn:
  -  Replace License by SDPX identifier
  -  Remove redundant inclusions
  -  Support tablet mode switch
  -  Simplify autorelease logic
  -  support panel front button
  -  support KEY_ROTATE_LOCK_TOGGLE
  -  Support separate press/release events
  -  support SW_TABLET_MODE
 
 intel_int0002_vgpio:
  -  Remove IRQF_NO_THREAD irq flag
 
 intel_pmc_core:
  -  Special case for Coffeelake
  -  Add CannonLake PCH support
  -  Read base address from LPIT
  -  Remove unused header file
  -  Convert to ICPU macro
  -  Substitute PCI with CPUID enumeration
  -  Refactor debugfs entries
  -  Update Kconfig
  -  Fix file permission warnings
  -  Change driver to a module
  -  Fix kernel doc for pmc_dev
  -  Remove unused variable
  -  Remove unused EXPORTED API
 
 intel_pmc_ipc:
  -  Add read64 API
 
 intel_telemetry:
  -  Remove redundancies
  -  Improve S0ix logs
  -  Fix suspend stats
 
 mlx-platform:
  -  Fix an ERR_PTR vs NULL issue
  -  Add hotplug device unregister to error path
  -  fix module aliases
  -  Add IO access verification callbacks
  -  Document pdev_hotplug field
  -  Allow compilation for 32 bit arch
 
 platform/mellanox:
  -  mlxreg-hotplug: Add check for negative adapter number
  -  mlxreg-hotplug: Enable building for ARM
  -  mlxreg-hotplug: Modify to use a regmap interface
  -  Group create/destroy with attribute functions
  -  Rename i2c bus to nr
  -  mlxreg-hotplug: Remove unused wait.h include
  -  Move Mellanox platform hotplug driver to platform/mellanox
 
 pmc_atom:
  -  introduce DEFINE_SHOW_ATTRIBUTE() macro
 
 samsung-laptop:
  -  Grammar s/are can/can/
 
 silead_dmi:
  -  Add Teclast X3 Plus tablet support
  -  Add entry for newer BIOS for Trekstor Surftab 7.0
  -  Add entry for the Teclast X98 Plus II
  -  Add entry for the Trekstor Primebook C13
  -  Add entry for the Chuwi Vi8 tablet
  -  add entry for Chuwi Hi8 tablet
  -  Add support for the Onda oBook 20 Plus tablet
  -  Add touchscreen info for SurfTab twin 10.1
 
 thinkpad_acpi:
  -  suppress warning about palm detection
  -  Accept flat mode for type 4 multi mode status
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Merge tag 'platform-drivers-x86-v4.16-1' of git://git.infradead.org/linux-platform-drivers-x86

Pull x86 platform-driver updates from Darren Hart:
 "New model support added for Dell, Ideapad, Acer, Asus, Thinkpad, and
  GPD laptops. Improvements to the common intel-vbtn driver, including
  tablet mode, rotate, and front button support. Intel CPU support added
  for Cannonlake and platform support for Dollar Cove power button.

  Overhaul of the mellanox platform driver, creating a new
  platform/mellanox directory for the newly multi-architecture regmap
  interface.

  Significant Intel PMC update with CannonLake support, Coffeelake
  update, CPUID enumeration, module support, new read64 API, refactoring
  and cleanups.

  Revert the apple-gmux iGP IO lock, addressing reported issues with
  non-binary drivers, leaving Nvidia binary driver users to comment out
  conflicting code.

  Miscellaneous fixes and cleanups"

* tag 'platform-drivers-x86-v4.16-1' of git://git.infradead.org/linux-platform-drivers-x86: (81 commits)
  platform/x86: mlx-platform: Fix an ERR_PTR vs NULL issue
  platform/x86: intel_pmc_core: Special case for Coffeelake
  platform/x86: intel_pmc_core: Add CannonLake PCH support
  x86/cpu: Add Cannonlake to Intel family
  platform/x86: intel_pmc_core: Read base address from LPIT
  ACPI / LPIT: Export lpit_read_residency_count_address()
  platform/x86: intel-vbtn: Replace License by SDPX identifier
  platform/x86: intel-vbtn: Remove redundant inclusions
  platform/x86: intel-vbtn: Support tablet mode switch
  platform/x86: dell-laptop: Allocate buffer on heap rather than globally
  platform/x86: intel_pmc_core: Remove unused header file
  platform/x86: mlx-platform: Add hotplug device unregister to error path
  platform/x86: mlx-platform: fix module aliases
  platform/mellanox: mlxreg-hotplug: Add check for negative adapter number
  platform/x86: mlx-platform: Add IO access verification callbacks
  platform/x86: mlx-platform: Document pdev_hotplug field
  platform/x86: mlx-platform: Allow compilation for 32 bit arch
  platform/mellanox: mlxreg-hotplug: Enable building for ARM
  platform/mellanox: mlxreg-hotplug: Modify to use a regmap interface
  platform/mellanox: Group create/destroy with attribute functions
  ...
2018-02-06 15:30:52 -08:00
..
obsolete This is the bulk of GPIO changes for the v4.15 kernel cycle: 2017-11-14 17:23:44 -08:00
removed rfkill: Remove obsolete "claim" sysfs interface 2016-02-24 09:04:24 +01:00
stable vmbus: add monitor_id and subchannel_id to sysfs per channel 2018-01-09 19:50:42 +01:00
testing platform-drivers-x86 for v4.16-1 2018-02-06 15:30:52 -08:00
README docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00

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.