Messages in this thread | | | Date | Tue, 29 Jan 2013 10:21:58 -0500 (EST) | From | Alan Stern <> | Subject | Re: [PATCH] usb: ehci: s5p: Power-off VBUS during suspend. |
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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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