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

Alan Stern
2012-05-11T20:26:06Z

On Fri, 11 May 2012, Sarah Sharp wrote:

> On Fri, May 11, 2012 at 07:54:04PM +0000, Lan, Tianyu wrote:
> > On 2012/5/12 1:44, Alan Stern wrote:
> > > This doesn't matter. Disconnections will be handled by
> > > usb_reset_and_verify_device(), when it is called by
> > > finish_port_resume().
> > This will cause the device to be re-enumerated. Just like
> > unplugged and plugged a device. I think this is not what
> > we want. Disconnect and create the same device. device
> > num is also change.
>
> Tianyu, do you have CONFIG_USB_PERSIST turned on?
>
> Alan, do you know if that will that only help in this case after the
> host controller PCI device is in D3hot?

See check_port_resume_type() in hub.c. It doesn't care what the reason
is for loss connectivity during suspend or what state the host
controller was in.

Alan Stern