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lf-6.6.y
linux-imx/Documentation/ABI/testing/sysfs-platform_profile
Hans de Goede b25d5a1cd1 ACPI: platform-profile: call sysfs_notify() from platform_profile_store() 
Drivers like thinkpad_acpi and ideapad_laptop call the
platform_profile_notify() helper when the profile is changed by hardware
(the embedded-controller/EC) in response to an EC handled hotkey.

This allows userspace to monitor for such changes by polling for POLLPRI
on the platform_profile sysfs file. But the profile can also be changed
underneath a userspace program monitoring it by anonther userspace program
storing a new value.

Add a sysfs_notify() call to platform_profile_store(), so that userspace
programs monitoring for changes also get notified in this case.

Also update the documentation to document that POLLPRI polling can be
used to watch for changes.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-08-16 18:32:02 +02:00

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What: /sys/firmware/acpi/platform_profile_choices Date: October 2020 Contact: Hans de Goede hdegoede@redhat.com Description: This file contains a space-separated list of profiles supported for this device.

	Drivers must use the following standard profile-names:

	====================	========================================
	low-power		Low power consumption
	cool			Cooler operation
	quiet			Quieter operation
	balanced		Balance between low power consumption
				and performance
	balanced-performance	Balance between performance and low
				power consumption with a slight bias
				towards performance
	performance		High performance operation
	====================	========================================

	Userspace may expect drivers to offer more than one of these
	standard profile names.

What: /sys/firmware/acpi/platform_profile Date: October 2020 Contact: Hans de Goede hdegoede@redhat.com Description: Reading this file gives the current selected profile for this device. Writing this file with one of the strings from platform_profile_choices changes the profile to the new value.

	This file can be monitored for changes by polling for POLLPRI,
	POLLPRI will be signalled on any changes, independent of those
	changes coming from a userspace write; or coming from another
	source such as e.g. a hotkey triggered profile change handled
	either directly by the embedded-controller or fully handled
	inside the kernel.