Unverified Commit 0056b085 authored by Mario Limonciello's avatar Mario Limonciello Committed by Ilpo Järvinen
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Documentation: Add documentation about class interface for platform profiles 



The class interface allows changing multiple platform profiles on a system
to different values. The semantics of it are similar to the legacy
interface.

Reviewed-by: default avatarArmin Wolf <W_Armin@gmx.de>
Tested-by: default avatarMark Pearson <mpearson-lenovo@squebb.ca>
Reviewed-by: default avatarMark Pearson <mpearson-lenovo@squebb.ca>
Reviewed-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20241206031918.1537-23-mario.limonciello@amd.com


Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
parent dd7ba84a

Documentation/ABI/testing/sysfs-platform_profile

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Original line number Diff line number Diff line
@@ -33,3 +33,8 @@ Description: Reading this file gives the current selected profile for this 
		source such as e.g. a hotkey triggered profile change handled

		either directly by the embedded-controller or fully handled

		inside the kernel.



		This file may also emit the string 'custom' to indicate

		that multiple platform profiles drivers are in use but

		have different values.  This string can not be written to

		this interface and is solely for informational purposes.

Documentation/userspace-api/sysfs-platform_profile.rst

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@@ -40,3 +40,41 @@ added. Drivers which wish to introduce new profile names must: 
 1. Explain why the existing profile names cannot be used.

 2. Add the new profile name, along with a clear description of the

    expected behaviour, to the sysfs-platform_profile ABI documentation.



"Custom" profile support

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

The platform_profile class also supports profiles advertising a "custom"

profile. This is intended to be set by drivers when the setttings in the

driver have been modified in a way that a standard profile doesn't represent

the current state.



Multiple driver support

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

When multiple drivers on a system advertise a platform profile handler, the

platform profile handler core will only advertise the profiles that are

common between all drivers to the ``/sys/firmware/acpi`` interfaces.



This is to ensure there is no ambiguity on what the profile names mean when

all handlers don't support a profile.



Individual drivers will register a 'platform_profile' class device that has

similar semantics as the ``/sys/firmware/acpi/platform_profile`` interface.



To discover which driver is associated with a platform profile handler the

user can read the ``name`` attribute of the class device.



To discover available profiles from the class interface the user can read the

``choices`` attribute.



If a user wants to select a profile for a specific driver, they can do so

by writing to the ``profile`` attribute of the driver's class device.



This will allow users to set different profiles for different drivers on the

same system. If the selected profile by individual drivers differs the

platform profile handler core will display the profile 'custom' to indicate

that the profiles are not the same.



While the ``platform_profile`` attribute has the value ``custom``, writing a

common profile from ``platform_profile_choices`` to the platform_profile

attribute of the platform profile handler core will set the profile for all

drivers.