Re: [RFC PATCH] usb/acpi: Add support usb port power off mechanism for device fixed on the motherboard

Lan Tianyu
2012-05-15T14:31:49Z

Since alan suggested we should start simpler version(power
down port that have no devices attached) firstly. And we
also should provide general power off mechanism.

I have a proposal.
first: add portx_power_control sys file.
echo "auto" => portx_power_control
check whether there is a device. if no, send the clear
USB_PORT_FEAT_POWER request. (since general way
to control port power is via set or clear PORT_POWER)

echo "on" => portx_power_control
send the set USB_PORT_FEAT_POWER request.

second:
In the xhci driver, add acpi hook in the xhci_hub_control()
where USB_PORT_FEAT_POWER request is dealt with.