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SubjectRe: [PATCH] Add driver to force WMI Thunderbolt controller power status
(Resending with a fixed CC list. Sorry.)

> Current implementations of Intel Thunderbolt controllers will go
> into a low power mode when not in use.

> Many machines containing these controllers also have a GPIO wired up
> that can force the controller awake.  This is offered via a ACPI-WMI
> interface intended to be manipulated by a userspace utility.

> This mechanism is provided by Intel to OEMs to include in BIOS.
> It uses an industry wide GUID that is populated in a separate _WDG
> entry with no binary MOF.

> This interface allow software such as fwupd to wake up thunderbolt
> controllers to query the firmware version or flash new firmware.

As this is a Thunderbolt specific function, maybe it's better to be
exposed from the Thunderbolt driver?

> +
> +static DEVICE_ATTR_WO(force_power);
> +

I'm not sure what is the convention for permissions for this type of
attributes but I feel like this worth being root-only writable, as it
can be used to power-off the controller in the middle of a FW update,
for example.
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