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authorLinus Torvalds <torvalds@linux-foundation.org>2020-10-16 15:02:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-16 15:02:21 -0700
commit54a4c789ca8091ab8fcd70285caeee2c5bc62997 (patch)
tree1bc7d8b12a9456505fb2cbe708f1c2aabbe69039 /Documentation/driver-api/pm/cpuidle.rst
parent93f3d8f54a22eaa5ae4ec269615729c4f9b1cf1e (diff)
parent3e2ac9798e13ad1f52d735ea2ea1d252cb140ae5 (diff)
Merge tag 'docs/v5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull documentation updates from Mauro Carvalho Chehab: "A series of patches addressing warnings produced by make htmldocs. This includes: - kernel-doc markup fixes - ReST fixes - Updates at the build system in order to support newer versions of the docs build toolchain (Sphinx) After this series, the number of html build warnings should reduce significantly, and building with Sphinx 3.1 or later should now be supported (although it is still recommended to use Sphinx 2.4.4). As agreed with Jon, I should be sending you a late pull request by the end of the merge window addressing remaining issues with docs build, as there are a number of warning fixes that depends on pull requests that should be happening along the merge window. The end goal is to have a clean htmldocs build on Kernel 5.10. PS. It should be noticed that Sphinx 3.0 is not currently supported, as it lacks support for C domain namespaces. Such feature, needed in order to document uAPI system calls with Sphinx 3.x, was added only on Sphinx 3.1" * tag 'docs/v5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (75 commits) PM / devfreq: remove a duplicated kernel-doc markup mm/doc: fix a literal block markup workqueue: fix a kernel-doc warning docs: virt: user_mode_linux_howto_v2.rst: fix a literal block markup Input: sparse-keymap: add a description for @sw rcu/tree: docs: document bkvcache new members at struct kfree_rcu_cpu nl80211: docs: add a description for s1g_cap parameter usb: docs: document altmode register/unregister functions kunit: test.h: fix a bad kernel-doc markup drivers: core: fix kernel-doc markup for dev_err_probe() docs: bio: fix a kerneldoc markup kunit: test.h: solve kernel-doc warnings block: bio: fix a warning at the kernel-doc markups docs: powerpc: syscall64-abi.rst: fix a malformed table drivers: net: hamradio: fix document location net: appletalk: Kconfig: Fix docs location dt-bindings: fix references to files converted to yaml memblock: get rid of a :c:type leftover math64.h: kernel-docs: Convert some markups into normal comments media: uAPI: buffer.rst: remove a left-over documentation ...
Diffstat (limited to 'Documentation/driver-api/pm/cpuidle.rst')
-rw-r--r--Documentation/driver-api/pm/cpuidle.rst65
1 files changed, 30 insertions, 35 deletions
diff --git a/Documentation/driver-api/pm/cpuidle.rst b/Documentation/driver-api/pm/cpuidle.rst
index 3588bf078566..d477208604b8 100644
--- a/Documentation/driver-api/pm/cpuidle.rst
+++ b/Documentation/driver-api/pm/cpuidle.rst
@@ -1,11 +1,6 @@
.. SPDX-License-Identifier: GPL-2.0
.. include:: <isonum.txt>
-.. |struct cpuidle_governor| replace:: :c:type:`struct cpuidle_governor <cpuidle_governor>`
-.. |struct cpuidle_device| replace:: :c:type:`struct cpuidle_device <cpuidle_device>`
-.. |struct cpuidle_driver| replace:: :c:type:`struct cpuidle_driver <cpuidle_driver>`
-.. |struct cpuidle_state| replace:: :c:type:`struct cpuidle_state <cpuidle_state>`
-
========================
CPU Idle Time Management
========================
@@ -54,7 +49,7 @@ platform that the Linux kernel can run on. For this reason, data structures
operated on by them cannot depend on any hardware architecture or platform
design details as well.
-The governor itself is represented by a |struct cpuidle_governor| object
+The governor itself is represented by a struct cpuidle_governor object
containing four callback pointers, :c:member:`enable`, :c:member:`disable`,
:c:member:`select`, :c:member:`reflect`, a :c:member:`rating` field described
below, and a name (string) used for identifying it.
@@ -83,11 +78,11 @@ callbacks:
int (*enable) (struct cpuidle_driver *drv, struct cpuidle_device *dev);
The role of this callback is to prepare the governor for handling the
- (logical) CPU represented by the |struct cpuidle_device| object pointed
- to by the ``dev`` argument. The |struct cpuidle_driver| object pointed
+ (logical) CPU represented by the struct cpuidle_device object pointed
+ to by the ``dev`` argument. The struct cpuidle_driver object pointed
to by the ``drv`` argument represents the ``CPUIdle`` driver to be used
with that CPU (among other things, it should contain the list of
- |struct cpuidle_state| objects representing idle states that the
+ struct cpuidle_state objects representing idle states that the
processor holding the given CPU can be asked to enter).
It may fail, in which case it is expected to return a negative error
@@ -102,7 +97,7 @@ callbacks:
void (*disable) (struct cpuidle_driver *drv, struct cpuidle_device *dev);
Called to make the governor stop handling the (logical) CPU represented
- by the |struct cpuidle_device| object pointed to by the ``dev``
+ by the struct cpuidle_device object pointed to by the ``dev``
argument.
It is expected to reverse any changes made by the ``->enable()``
@@ -116,12 +111,12 @@ callbacks:
bool *stop_tick);
Called to select an idle state for the processor holding the (logical)
- CPU represented by the |struct cpuidle_device| object pointed to by the
+ CPU represented by the struct cpuidle_device object pointed to by the
``dev`` argument.
The list of idle states to take into consideration is represented by the
- :c:member:`states` array of |struct cpuidle_state| objects held by the
- |struct cpuidle_driver| object pointed to by the ``drv`` argument (which
+ :c:member:`states` array of struct cpuidle_state objects held by the
+ struct cpuidle_driver object pointed to by the ``drv`` argument (which
represents the ``CPUIdle`` driver to be used with the CPU at hand). The
value returned by this callback is interpreted as an index into that
array (unless it is a negative error code).
@@ -136,7 +131,7 @@ callbacks:
asking the processor to enter the idle state).
This callback is mandatory (i.e. the :c:member:`select` callback pointer
- in |struct cpuidle_governor| must not be ``NULL`` for the registration
+ in struct cpuidle_governor must not be ``NULL`` for the registration
of the governor to succeed).
:c:member:`reflect`
@@ -167,21 +162,21 @@ CPU idle time management (``CPUIdle``) drivers provide an interface between the
other parts of ``CPUIdle`` and the hardware.
First of all, a ``CPUIdle`` driver has to populate the :c:member:`states` array
-of |struct cpuidle_state| objects included in the |struct cpuidle_driver| object
+of struct cpuidle_state objects included in the struct cpuidle_driver object
representing it. Going forward this array will represent the list of available
idle states that the processor hardware can be asked to enter shared by all of
the logical CPUs handled by the given driver.
The entries in the :c:member:`states` array are expected to be sorted by the
-value of the :c:member:`target_residency` field in |struct cpuidle_state| in
+value of the :c:member:`target_residency` field in struct cpuidle_state in
the ascending order (that is, index 0 should correspond to the idle state with
the minimum value of :c:member:`target_residency`). [Since the
:c:member:`target_residency` value is expected to reflect the "depth" of the
-idle state represented by the |struct cpuidle_state| object holding it, this
+idle state represented by the struct cpuidle_state object holding it, this
sorting order should be the same as the ascending sorting order by the idle
state "depth".]
-Three fields in |struct cpuidle_state| are used by the existing ``CPUIdle``
+Three fields in struct cpuidle_state are used by the existing ``CPUIdle``
governors for computations related to idle state selection:
:c:member:`target_residency`
@@ -203,7 +198,7 @@ governors for computations related to idle state selection:
any idle state at all. [There are other flags used by the ``CPUIdle``
core in special situations.]
-The :c:member:`enter` callback pointer in |struct cpuidle_state|, which must not
+The :c:member:`enter` callback pointer in struct cpuidle_state, which must not
be ``NULL``, points to the routine to execute in order to ask the processor to
enter this particular idle state:
@@ -212,14 +207,14 @@ enter this particular idle state:
void (*enter) (struct cpuidle_device *dev, struct cpuidle_driver *drv,
int index);
-The first two arguments of it point to the |struct cpuidle_device| object
+The first two arguments of it point to the struct cpuidle_device object
representing the logical CPU running this callback and the
-|struct cpuidle_driver| object representing the driver itself, respectively,
-and the last one is an index of the |struct cpuidle_state| entry in the driver's
+struct cpuidle_driver object representing the driver itself, respectively,
+and the last one is an index of the struct cpuidle_state entry in the driver's
:c:member:`states` array representing the idle state to ask the processor to
enter.
-The analogous ``->enter_s2idle()`` callback in |struct cpuidle_state| is used
+The analogous ``->enter_s2idle()`` callback in struct cpuidle_state is used
only for implementing the suspend-to-idle system-wide power management feature.
The difference between in and ``->enter()`` is that it must not re-enable
interrupts at any point (even temporarily) or attempt to change the states of
@@ -227,48 +222,48 @@ clock event devices, which the ``->enter()`` callback may do sometimes.
Once the :c:member:`states` array has been populated, the number of valid
entries in it has to be stored in the :c:member:`state_count` field of the
-|struct cpuidle_driver| object representing the driver. Moreover, if any
+struct cpuidle_driver object representing the driver. Moreover, if any
entries in the :c:member:`states` array represent "coupled" idle states (that
is, idle states that can only be asked for if multiple related logical CPUs are
-idle), the :c:member:`safe_state_index` field in |struct cpuidle_driver| needs
+idle), the :c:member:`safe_state_index` field in struct cpuidle_driver needs
to be the index of an idle state that is not "coupled" (that is, one that can be
asked for if only one logical CPU is idle).
In addition to that, if the given ``CPUIdle`` driver is only going to handle a
subset of logical CPUs in the system, the :c:member:`cpumask` field in its
-|struct cpuidle_driver| object must point to the set (mask) of CPUs that will be
+struct cpuidle_driver object must point to the set (mask) of CPUs that will be
handled by it.
A ``CPUIdle`` driver can only be used after it has been registered. If there
are no "coupled" idle state entries in the driver's :c:member:`states` array,
-that can be accomplished by passing the driver's |struct cpuidle_driver| object
+that can be accomplished by passing the driver's struct cpuidle_driver object
to :c:func:`cpuidle_register_driver()`. Otherwise, :c:func:`cpuidle_register()`
should be used for this purpose.
-However, it also is necessary to register |struct cpuidle_device| objects for
+However, it also is necessary to register struct cpuidle_device objects for
all of the logical CPUs to be handled by the given ``CPUIdle`` driver with the
help of :c:func:`cpuidle_register_device()` after the driver has been registered
and :c:func:`cpuidle_register_driver()`, unlike :c:func:`cpuidle_register()`,
does not do that automatically. For this reason, the drivers that use
:c:func:`cpuidle_register_driver()` to register themselves must also take care
-of registering the |struct cpuidle_device| objects as needed, so it is generally
+of registering the struct cpuidle_device objects as needed, so it is generally
recommended to use :c:func:`cpuidle_register()` for ``CPUIdle`` driver
registration in all cases.
-The registration of a |struct cpuidle_device| object causes the ``CPUIdle``
+The registration of a struct cpuidle_device object causes the ``CPUIdle``
``sysfs`` interface to be created and the governor's ``->enable()`` callback to
be invoked for the logical CPU represented by it, so it must take place after
registering the driver that will handle the CPU in question.
-``CPUIdle`` drivers and |struct cpuidle_device| objects can be unregistered
+``CPUIdle`` drivers and struct cpuidle_device objects can be unregistered
when they are not necessary any more which allows some resources associated with
them to be released. Due to dependencies between them, all of the
-|struct cpuidle_device| objects representing CPUs handled by the given
+struct cpuidle_device objects representing CPUs handled by the given
``CPUIdle`` driver must be unregistered, with the help of
:c:func:`cpuidle_unregister_device()`, before calling
:c:func:`cpuidle_unregister_driver()` to unregister the driver. Alternatively,
:c:func:`cpuidle_unregister()` can be called to unregister a ``CPUIdle`` driver
-along with all of the |struct cpuidle_device| objects representing CPUs handled
+along with all of the struct cpuidle_device objects representing CPUs handled
by it.
``CPUIdle`` drivers can respond to runtime system configuration changes that
@@ -277,8 +272,8 @@ happen, for example, when the system's power source is switched from AC to
battery or the other way around). Upon a notification of such a change,
a ``CPUIdle`` driver is expected to call :c:func:`cpuidle_pause_and_lock()` to
turn ``CPUIdle`` off temporarily and then :c:func:`cpuidle_disable_device()` for
-all of the |struct cpuidle_device| objects representing CPUs affected by that
+all of the struct cpuidle_device objects representing CPUs affected by that
change. Next, it can update its :c:member:`states` array in accordance with
the new configuration of the system, call :c:func:`cpuidle_enable_device()` for
-all of the relevant |struct cpuidle_device| objects and invoke
+all of the relevant struct cpuidle_device objects and invoke
:c:func:`cpuidle_resume_and_unlock()` to allow ``CPUIdle`` to be used again.