Merge branch 'linus' into irq/core

If the userspace hasn't been prepared to ignore the unreliable "opened"

events and the unreliable initial state notification, Linux users can use

the following kernel parameters to handle the possible issues:

A. button.lid_init_state=open:

A. button.lid_init_state=method:

   When this option is specified, the ACPI button driver reports the

   initial lid state using the returning value of the _LID control method

   and whether the "opened"/"closed" events are paired fully relies on the

   firmware implementation.

   This option can be used to fix some platforms where the returning value

   of the _LID control method is reliable but the initial lid state

   notification is missing.

   This option is the default behavior during the period the userspace

   isn't ready to handle the buggy AML tables.

B. button.lid_init_state=open:

   When this option is specified, the ACPI button driver always reports the

   initial lid state as "opened" and whether the "opened"/"closed" events

   are paired fully relies on the firmware implementation.

   This may fix some platforms where the returning value of the _LID

   control method is not reliable and the initial lid state notification is

   missing.

   This option is the default behavior during the period the userspace

   isn't ready to handle the buggy AML tables.

If the userspace has been prepared to ignore the unreliable "opened" events

and the unreliable initial state notification, Linux users should always

use the following kernel parameter:

B. button.lid_init_state=ignore:

C. button.lid_init_state=ignore:

   When this option is specified, the ACPI button driver never reports the

   initial lid state and there is a compensation mechanism implemented to

   ensure that the reliable "closed" notifications can always be delievered

	dscc4.setup=	[NET]

	dt_cpu_ftrs=	[PPC]

			Format: {"off" | "known"}

			Control how the dt_cpu_ftrs device-tree binding is

			used for CPU feature discovery and setup (if it

			exists).

			off: Do not use it, fall back to legacy cpu table.

			known: Do not pass through unknown features to guests

			or userspace, only those that the kernel is aware of.

	dump_apple_properties	[X86]

			Dump name and content of EFI device properties on

			x86 Macs.  Useful for driver authors to determine

			expediting.  Set to zero to disable automatic

			expediting.

	stack_guard_gap=	[MM]

			override the default stack gap protection. The value

			is in page units and it defines how many pages prior

			to (for stacks growing down) resp. after (for stacks

			growing up) the main stack are reserved for no other

			mapping. Default value is 256 pages.

	stacktrace	[FTRACE]

			Enabled the stack tracer on boot up.

.. |struct cpufreq_policy| replace:: :c:type:`struct cpufreq_policy <cpufreq_policy>`

.. |intel_pstate| replace:: :doc:`intel_pstate <intel_pstate>`

=======================

CPU Performance Scaling

interface it comes from and may not be easily represented in an abstract,

platform-independent way.  For this reason, ``CPUFreq`` allows scaling drivers

to bypass the governor layer and implement their own performance scaling

algorithms.  That is done by the ``intel_pstate`` scaling driver.

algorithms.  That is done by the |intel_pstate| scaling driver.

``CPUFreq`` Policy Objects

into account.  That is achieved by invoking the governor's ``->stop`` and

``->start()`` callbacks, in this order, for the entire policy.

As mentioned before, the ``intel_pstate`` scaling driver bypasses the scaling

As mentioned before, the |intel_pstate| scaling driver bypasses the scaling

governor layer of ``CPUFreq`` and provides its own P-state selection algorithms.

Consequently, if ``intel_pstate`` is used, scaling governors are not attached to

Consequently, if |intel_pstate| is used, scaling governors are not attached to

new policy objects.  Instead, the driver's ``->setpolicy()`` callback is invoked

to register per-CPU utilization update callbacks for each policy.  These

callbacks are invoked by the CPU scheduler in the same way as for scaling

governors, but in the ``intel_pstate`` case they both determine the P-state to

governors, but in the |intel_pstate| case they both determine the P-state to

use and change the hardware configuration accordingly in one go from scheduler

context.

``scaling_available_governors``

	List of ``CPUFreq`` scaling governors present in the kernel that can

	be attached to this policy or (if the ``intel_pstate`` scaling driver is

	be attached to this policy or (if the |intel_pstate| scaling driver is

	in use) list of scaling algorithms provided by the driver that can be

	applied to this policy.

	the CPU is actually running at (due to hardware design and other

	limitations).

	Some scaling drivers (e.g. ``intel_pstate``) attempt to provide

	Some scaling drivers (e.g. |intel_pstate|) attempt to provide

	information more precisely reflecting the current CPU frequency through

	this attribute, but that still may not be the exact current CPU

	frequency as seen by the hardware at the moment.

``scaling_governor``

	The scaling governor currently attached to this policy or (if the

	``intel_pstate`` scaling driver is in use) the scaling algorithm

	|intel_pstate| scaling driver is in use) the scaling algorithm

	provided by the driver that is currently applied to this policy.

	This attribute is read-write and writing to it will cause a new scaling

	governor to be attached to this policy or a new scaling algorithm

	provided by the scaling driver to be applied to it (in the

	``intel_pstate`` case), as indicated by the string written to this

	|intel_pstate| case), as indicated by the string written to this

	attribute (which must be one of the names listed by the

	``scaling_available_governors`` attribute described above).

the "boost" setting for the whole system.  It is not present if the underlying

scaling driver does not support the frequency boost mechanism (or supports it,

but provides a driver-specific interface for controlling it, like

``intel_pstate``).

|intel_pstate|).

If the value in this file is 1, the frequency boost mechanism is enabled.  This

means that either the hardware can be put into states in which it is able to

   :maxdepth: 2

   cpufreq

   intel_pstate

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