Re: [PATCH v3 1/2] usb: ohci-at91: Forcibly suspend ports while USB suspend

Alan Stern
2016-06-08T19:14:01Z

On Wed, 8 Jun 2016, Wenyou Yang wrote:

> In order to the save power consumption, as a workaround, suspend
> forcibly the USB PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI
> Interrupt Configuration Register in the SFRs while OHCI USB suspend.
>
> This suspend operation must be done before the USB clock is disabled,
> resume after the USB clock is enabled.
>
> Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
> ---

You never answered the questions I posted for the first version of this
patch:

What does this mean? What does suspending a port do? Is it the same
as a normal USB port suspend?

If it is the same, why doesn't the USB_PORT_FEAT_SUSPEND subcase of the
SetPortFeature case in ohci_hub_control() already take care of this?

Alan Stern