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

Sarah Sharp
2012-05-15T20:01:01Z

On Tue, May 15, 2012 at 08:18:00AM -0700, Greg KH wrote:
> On Tue, May 15, 2012 at 10:31:38PM +0800, Lan Tianyu wrote:
> > 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.
>
> No "off"?

Yeah, we probably need an "off" for those libusb and ModemManager
developers who want to try and simulate a disconnect of a misbehaving
device.

Sarah Sharp