Merge tag 'acpi-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI updates from Rafael Wysocki:
 "The ACPICA code in the kernel gets updated as usual (included is
  upstream revision 20160930 and a few commits from the next one, with
  the rest waiting for an issue discovered in linux-next to be
  addressed) which brings in a couple of fixes and cleanups

  On top of that initial support for APEI on ARM64 is added, two new
  pieces of documentation are introduced, the properties-parsing code is
  updated to follow changes in the (external) documentation it is based
  on and there are a few updates of SoC drivers, some new blacklist
  entries, plus some assorted fixes and cleanups

  Specifics:

   - ACPICA update including upstream revision 20160930 and several
     commits beyond it (Bob Moore, Lv Zheng)

   - Initial support for ACPI APEI on ARM64 (Tomasz Nowicki)

   - New document describing the handling of _OSI and _REV in Linux (Len
     Brown)

   - New document describing the usage rules for _DSD properties (Rafael
     Wysocki)

   - Update of the ACPI properties-parsing code to reflect recent
     changes in the (external) documentation it is based on (Rafael
     Wysocki)

   - Updates of the ACPI LPSS and ACPI APD SoC drivers for additional
     hardware support (Andy Shevchenko, Nehal Shah)

   - New blacklist entries for _REV and video handling (Alex Hung, Hans
     de Goede, Michael Pobega)

   - ACPI battery driver fix to fall back to _BIF if _BIX fails (Dave
     Lambley)

   - NMI notifications handling fix for APEI (Prarit Bhargava)

   - Error code path fix for the ACPI CPPC library (Dan Carpenter)

   - Assorted cleanups (Andy Shevchenko, Longpeng Mike)"

* tag 'acpi-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (31 commits)
  ACPICA: Utilities: Add new decode function for parser values
  ACPI / osl: Refactor acpi_os_get_root_pointer() to drop 'else':s
  ACPI / osl: Propagate actual error code for kstrtoul()
  ACPI / property: Document usage rules for _DSD properties
  ACPI: Document _OSI and _REV for Linux BIOS writers
  ACPI / APEI / ARM64: APEI initial support for ARM64
  ACPI / APEI: Fix NMI notification handling
  ACPICA: Tables: Add an error message complaining driver bugs
  ACPICA: Tables: Add acpi_tb_unload_table()
  ACPICA: Tables: Cleanup acpi_tb_install_and_load_table()
  ACPICA: Events: Fix acpi_ev_initialize_region() return value
  ACPICA: Back port of "ACPICA: Dispatcher: Tune interpreter lock around AcpiEvInitializeRegion()"
  ACPICA: Namespace: Add acpi_ns_handle_to_name()
  ACPI / CPPC: set an error code on probe error path
  ACPI / video: Add force_native quirk for HP Pavilion dv6
  ACPI / video: Add force_native quirk for Dell XPS 17 L702X
  ACPI / property: Hierarchical properties support update
  ACPI / LPSS: enable hard LLP for DMA
  ACPI / battery: If _BIX fails, retry with _BIF
  ACPI / video: Move ACPI_VIDEO_NOTIFY_* defines to acpi/video.h
  ..

3 files changed, 293 insertions, 0 deletions

diff --git a/Documentation/acpi/DSD-properties-rules.txt b/Documentation/acpi/DSD-properties-rules.txt
new file mode 100644
index 0000000..3e4862b
--- /dev/null
+++ b/Documentation/acpi/DSD-properties-rules.txt
@@ -0,0 +1,97 @@
+_DSD Device Properties Usage Rules
+----------------------------------
+
+Properties, Property Sets and Property Subsets
+----------------------------------------------
+
+The _DSD (Device Specific Data) configuration object, introduced in ACPI 5.1,
+allows any type of device configuration data to be provided via the ACPI
+namespace.  In principle, the format of the data may be arbitrary, but it has to
+be identified by a UUID which must be recognized by the driver processing the
+_DSD output.  However, there are generic UUIDs defined for _DSD recognized by
+the ACPI subsystem in the Linux kernel which automatically processes the data
+packages associated with them and makes those data available to device drivers
+as "device properties".
+
+A device property is a data item consisting of a string key and a value (of a
+specific type) associated with it.
+
+In the ACPI _DSD context it is an element of the sub-package following the
+generic Device Properties UUID in the _DSD return package as specified in the
+Device Properties UUID definition document [1].
+
+It also may be regarded as the definition of a key and the associated data type
+that can be returned by _DSD in the Device Properties UUID sub-package for a
+given device.
+
+A property set is a collection of properties applicable to a hardware entity
+like a device.  In the ACPI _DSD context it is the set of all properties that
+can be returned in the Device Properties UUID sub-package for the device in
+question.
+
+Property subsets are nested collections of properties.  Each of them is
+associated with an additional key (name) allowing the subset to be referred
+to as a whole (and to be treated as a separate entity).  The canonical
+representation of property subsets is via the mechanism specified in the
+Hierarchical Properties Extension UUID definition document [2].
+
+Property sets may be hierarchical.  That is, a property set may contain
+multiple property subsets that each may contain property subsets of its
+own and so on.
+
+General Validity Rule for Property Sets
+---------------------------------------
+
+Valid property sets must follow the guidance given by the Device Properties UUID
+definition document [1].
+
+_DSD properties are intended to be used in addition to, and not instead of, the
+existing mechanisms defined by the ACPI specification.  Therefore, as a rule,
+they should only be used if the ACPI specification does not make direct
+provisions for handling the underlying use case.  It generally is invalid to
+return property sets which do not follow that rule from _DSD in data packages
+associated with the Device Properties UUID.
+
+Additional Considerations
+-------------------------
+
+There are cases in which, even if the general rule given above is followed in
+principle, the property set may still not be regarded as a valid one.
+
+For example, that applies to device properties which may cause kernel code
+(either a device driver or a library/subsystem) to access hardware in a way
+possibly leading to a conflict with AML methods in the ACPI namespace.  In
+particular, that may happen if the kernel code uses device properties to
+manipulate hardware normally controlled by ACPI methods related to power
+management, like _PSx and _DSW (for device objects) or _ON and _OFF (for power
+resource objects), or by ACPI device disabling/enabling methods, like _DIS and
+_SRS.
+
+In all cases in which kernel code may do something that will confuse AML as a
+result of using device properties, the device properties in question are not
+suitable for the ACPI environment and consequently they cannot belong to a valid
+property set.
+
+Property Sets and Device Tree Bindings
+--------------------------------------
+
+It often is useful to make _DSD return property sets that follow Device Tree
+bindings.
+
+In those cases, however, the above validity considerations must be taken into
+account in the first place and returning invalid property sets from _DSD must be
+avoided.  For this reason, it may not be possible to make _DSD return a property
+set following the given DT binding literally and completely.  Still, for the
+sake of code re-use, it may make sense to provide as much of the configuration
+data as possible in the form of device properties and complement that with an
+ACPI-specific mechanism suitable for the use case at hand.
+
+In any case, property sets following DT bindings literally should not be
+expected to automatically work in the ACPI environment regardless of their
+contents.
+
+References
+----------
+
+[1] http://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf
+[2] http://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.1.pdf
diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
index a91ec5a..209a5eb 100644
--- a/Documentation/acpi/enumeration.txt
+++ b/Documentation/acpi/enumeration.txt
@@ -415,3 +415,12 @@ the "compatible" property in the _DSD or a _CID as long as one of their
 ancestors provides a _DSD with a valid "compatible" property.  Such device
 objects are then simply regarded as additional "blocks" providing hierarchical
 configuration information to the driver of the composite ancestor device.
+
+However, PRP0001 can only be returned from either _HID or _CID of a device
+object if all of the properties returned by the _DSD associated with it (either
+the _DSD of the device object itself or the _DSD of its ancestor in the
+"composite device" case described above) can be used in the ACPI environment.
+Otherwise, the _DSD itself is regarded as invalid and therefore the "compatible"
+property returned by it is meaningless.
+
+Refer to DSD-properties-rules.txt for more information.
diff --git a/Documentation/acpi/osi.txt b/Documentation/acpi/osi.txt
new file mode 100644
index 0000000..50cde0c
--- /dev/null
+++ b/Documentation/acpi/osi.txt
@@ -0,0 +1,187 @@
+ACPI _OSI and _REV methods
+--------------------------
+
+An ACPI BIOS can use the "Operating System Interfaces" method (_OSI)
+to find out what the operating system supports. Eg. If BIOS
+AML code includes _OSI("XYZ"), the kernel's AML interpreter
+can evaluate that method, look to see if it supports 'XYZ'
+and answer YES or NO to the BIOS.
+
+The ACPI _REV method returns the "Revision of the ACPI specification
+that OSPM supports"
+
+This document explains how and why the BIOS and Linux should use these methods.
+It also explains how and why they are widely misused.
+
+How to use _OSI
+---------------
+
+Linux runs on two groups of machines -- those that are tested by the OEM
+to be compatible with Linux, and those that were never tested with Linux,
+but where Linux was installed to replace the original OS (Windows or OSX).
+
+The larger group is the systems tested to run only Windows.  Not only that,
+but many were tested to run with just one specific version of Windows.
+So even though the BIOS may use _OSI to query what version of Windows is running,
+only a single path through the BIOS has actually been tested.
+Experience shows that taking untested paths through the BIOS
+exposes Linux to an entire category of BIOS bugs.
+For this reason, Linux _OSI defaults must continue to claim compatibility
+with all versions of Windows.
+
+But Linux isn't actually compatible with Windows, and the Linux community
+has also been hurt with regressions when Linux adds the latest version of
+Windows to its list of _OSI strings.  So it is possible that additional strings
+will be more thoroughly vetted before shipping upstream in the future.
+But it is likely that they will all eventually be added.
+
+What should an OEM do if they want to support Linux and Windows
+using the same BIOS image?  Often they need to do something different
+for Linux to deal with how Linux is different from Windows.
+Here the BIOS should ask exactly what it wants to know:
+
+_OSI("Linux-OEM-my_interface_name")
+where 'OEM' is needed if this is an OEM-specific hook,
+and 'my_interface_name' describes the hook, which could be a
+quirk, a bug, or a bug-fix.
+
+In addition, the OEM should send a patch to upstream Linux
+via the linux-acpi@vger.kernel.org mailing list.  When that patch
+is checked into Linux, the OS will answer "YES" when the BIOS
+on the OEM's system uses _OSI to ask if the interface is supported
+by the OS.  Linux distributors can back-port that patch for Linux
+pre-installs, and it will be included by all distributions that
+re-base to upstream.  If the distribution can not update the kernel binary,
+they can also add an acpi_osi=Linux-OEM-my_interface_name
+cmdline parameter to the boot loader, as needed.
+
+If the string refers to a feature where the upstream kernel
+eventually grows support, a patch should be sent to remove
+the string when that support is added to the kernel.
+
+That was easy.  Read on, to find out how to do it wrong.
+
+Before _OSI, there was _OS
+--------------------------
+
+ACPI 1.0 specified "_OS" as an
+"object that evaluates to a string that identifies the operating system."
+
+The ACPI BIOS flow would include an evaluation of _OS, and the AML
+interpreter in the kernel would return to it a string identifying the OS:
+
+Windows 98, SE: "Microsoft Windows"
+Windows ME: "Microsoft WindowsME:Millenium Edition"
+Windows NT: "Microsoft Windows NT"
+
+The idea was on a platform tasked with running multiple OS's,
+the BIOS could use _OS to enable devices that an OS
+might support, or enable quirks or bug workarounds
+necessary to make the platform compatible with that pre-existing OS.
+
+But _OS had fundamental problems.  First, the BIOS needed to know the name
+of every possible version of the OS that would run on it, and needed to know
+all the quirks of those OS's.  Certainly it would make more sense
+for the BIOS to ask *specific* things of the OS, such
+"do you support a specific interface", and thus in ACPI 3.0,
+_OSI was born to replace _OS.
+
+_OS was abandoned, though even today, many BIOS look for
+_OS "Microsoft Windows NT", though it seems somewhat far-fetched
+that anybody would install those old operating systems
+over what came with the machine.
+
+Linux answers "Microsoft Windows NT" to please that BIOS idiom.
+That is the *only* viable strategy, as that is what modern Windows does,
+and so doing otherwise could steer the BIOS down an untested path.
+
+_OSI is born, and immediately misused
+--------------------------------------
+
+With _OSI, the *BIOS* provides the string describing an interface,
+and asks the OS: "YES/NO, are you compatible with this interface?"
+
+eg. _OSI("3.0 Thermal Model") would return TRUE if the OS knows how
+to deal with the thermal extensions made to the ACPI 3.0 specification.
+An old OS that doesn't know about those extensions would answer FALSE,
+and a new OS may be able to return TRUE.
+
+For an OS-specific interface, the ACPI spec said that the BIOS and the OS
+were to agree on a string of the form such as "Windows-interface_name".
+
+But two bad things happened.  First, the Windows ecosystem used _OSI
+not as designed, but as a direct replacement for _OS -- identifying
+the OS version, rather than an OS supported interface.  Indeed, right
+from the start, the ACPI 3.0 spec itself codified this misuse
+in example code using _OSI("Windows 2001").
+
+This misuse was adopted and continues today.
+
+Linux had no choice but to also return TRUE to _OSI("Windows 2001")
+and its successors.  To do otherwise would virtually guarantee breaking
+a BIOS that has been tested only with that _OSI returning TRUE.
+
+This strategy is problematic, as Linux is never completely compatible with
+the latest version of Windows, and sometimes it takes more than a year
+to iron out incompatibilities.
+
+Not to be out-done, the Linux community made things worse by returning TRUE
+to _OSI("Linux").  Doing so is even worse than the Windows misuse
+of _OSI, as "Linux" does not even contain any version information.
+_OSI("Linux") led to some BIOS' malfunctioning due to BIOS writer's
+using it in untested BIOS flows.  But some OEM's used _OSI("Linux")
+in tested flows to support real Linux features.  In 2009, Linux
+removed _OSI("Linux"), and added a cmdline parameter to restore it
+for legacy systems still needed it.  Further a BIOS_BUG warning prints
+for all BIOS's that invoke it.
+
+No BIOS should use _OSI("Linux").
+
+The result is a strategy for Linux to maximize compatibility with
+ACPI BIOS that are tested on Windows machines.  There is a real risk
+of over-stating that compatibility; but the alternative has often been
+catastrophic failure resulting from the BIOS taking paths that
+were never validated under *any* OS.
+
+Do not use _REV
+---------------
+
+Since _OSI("Linux") went away, some BIOS writers used _REV
+to support Linux and Windows differences in the same BIOS.
+
+_REV was defined in ACPI 1.0 to return the version of ACPI
+supported by the OS and the OS AML interpreter.
+
+Modern Windows returns _REV = 2.  Linux used ACPI_CA_SUPPORT_LEVEL,
+which would increment, based on the version of the spec supported.
+
+Unfortunately, _REV was also misused.  eg. some BIOS would check
+for _REV = 3, and do something for Linux, but when Linux returned
+_REV = 4, that support broke.
+
+In response to this problem, Linux returns _REV = 2 always,
+from mid-2015 onward.  The ACPI specification will also be updated
+to reflect that _REV is deprecated, and always returns 2.
+
+Apple Mac and _OSI("Darwin")
+----------------------------
+
+On Apple's Mac platforms, the ACPI BIOS invokes _OSI("Darwin")
+to determine if the machine is running Apple OSX.
+
+Like Linux's _OSI("*Windows*") strategy, Linux defaults to
+answering YES to _OSI("Darwin") to enable full access
+to the hardware and validated BIOS paths seen by OSX.
+Just like on Windows-tested platforms, this strategy has risks.
+
+Starting in Linux-3.18, the kernel answered YES to _OSI("Darwin")
+for the purpose of enabling Mac Thunderbolt support.  Further,
+if the kernel noticed _OSI("Darwin") being invoked, it additionally
+disabled all _OSI("*Windows*") to keep poorly written Mac BIOS
+from going down untested combinations of paths.
+
+The Linux-3.18 change in default caused power regressions on Mac
+laptops, and the 3.18 implementation did not allow changing
+the default via cmdline "acpi_osi=!Darwin".  Linux-4.7 fixed
+the ability to use acpi_osi=!Darwin as a workaround, and
+we hope to see Mac Thunderbolt power management support in Linux-4.11.