Documentation: PM: amd-pstate: Fix section title underline

Title under line too short

Signed-off-by: Meng Li <li.meng@amd.com>
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: amd-pstate: introduce amd-pstate preferred core

Introduce amd-pstate preferred core.

check preferred core state set by the kernel parameter:
$ cat /sys/devices/system/cpu/amd-pstate/prefcore

Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Meng Li <li.meng@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: admin-guide: PM: Fix two typos

Fix two typos in the admin-guide:

- a missing e in "reference_perf" in cppc_sysfs.rst.
- the amd_pstate sysfs path uses a dash instead of an underscore.

Signed-off-by: Erwan Velu <e.velu@criteo.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: cpufreq: amd-pstate: Update amd_pstate status sysfs for guided

Update amd_pstate status sysfs for guided mode.

Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: admin-guide: correct spelling

Correct spelling problems for Documentation/admin-guide/ as reported
by codespell.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: dm-devel@redhat.com
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org
Cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20230129231053.20863-2-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation: amd-pstate: disambiguate user space sections

kernel test robot reported htmldocs warning:

Documentation/admin-guide/pm/amd-pstate.rst:343: WARNING: duplicate label admin-guide/pm/amd-pstate:user space interface in ``sysfs``, other instance in Documentation/admin-guide/pm/amd-pstate.rst

The documentation contains two sections with the same "User Space Interface
in ``sysfs``" title. The first one deals with per-policy sysfs and the
second one is about general attributes (currently only global attributes
are documented).

Disambiguate title text of both sections to fix the warning.

Link: https://lore.kernel.org/linux-doc/202302151041.0SWs1RHK-lkp@intel.com/
Fixes: b9e6a2d47b2565 ("Documentation: amd-pstate: introduce new global sysfs attributes")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: amd-pstate: introduce new global sysfs attributes

The amd-pstate driver supports switching working modes at runtime.
Users can view and change modes by interacting with the "status" sysfs
attribute.

1) check driver mode:
$ cat /sys/devices/system/cpu/amd-pstate/status

2) switch mode:
`# echo "passive" | sudo tee /sys/devices/system/cpu/amd-pstate/status`
or
`# echo "active" | sudo tee /sys/devices/system/cpu/amd-pstate/status`

Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: amd-pstate: add amd pstate driver mode introduction

The amd-pstate driver has two operation modes supported:
* CPPC Autonomous (active) mode
* CPPC non-autonomous (passive) mode.
active mode and passive mode can be chosen by different kernel parameters.

Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: amd-pstate: add EPP profiles introduction

The amd-pstate driver supports a feature called energy performance
preference (EPP). Add information to the documentation to explain
how users can interact with the sysfs files for this feature.

1) See all EPP profiles
$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_available_preferences
default performance balance_performance balance_power power

2) Check current EPP profile
$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference
performance

3) Set new EPP profile
$ sudo bash -c "echo power > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference"

Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: amd-pstate: Add tbench and gitsource test introduction

Introduce tbench and gitsource test cases design and implementation.
Monitor cpus changes about performance and power consumption etc.

Signed-off-by: Meng Li <li.meng@amd.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Documentation: amd-pstate: add driver working mode introduction

Introduce the `amd_pstate` driver new working mode with
`amd_pstate=passive` added to kernel command line.
If there is no passive mode enabled by user, amd_pstate driver will be
disabled by default for now.

Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: amd-pstate: Add unit test introduction

Introduce the AMD P-State unit test module design and implementation.
It also talks about kselftest and how to use.

Signed-off-by: Meng Li <li.meng@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Documentation: amd-pstate: grammar and sentence structure updates

Signed-off-by: Jan Engelhardt <jengelh@inai.de>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: amd-pstate: add tracer tool introduction

Add amd pstate tracer tool introduction

Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation: amd-pstate: Add AMD P-State driver introduction

Introduce the AMD P-State driver design and implementation.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>