Re: [PATCH] usb: ehci: s5p: Power-off VBUS during suspend.

[Alan Stern]

On Tue, 29 Jan 2013, Vivek Gautam wrote:

> This change de-asserts vbus_gpio on suspend and
> re-asserts on resume in order to save power.
> NOTE, this change means no USB charging in suspend
> mode.

Doing this would mean USB devices could not wake up the system.  This 
would be unacceptable.

However, turning off VBUS power is okay provided:

	no root-hub ports are enabled, and

	the root hub is not enabled for wakeup.

Under those circumstances there can't be any wakeup-enabled USB devices 
on the bus, and the root hub itself would not need to detect new 
connections and disconnections.

Alan Stern

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