Thread (20 messages) 20 messages, 5 authors, 2016-06-20

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

From: Alan Stern <hidden>
Date: 2016-06-08 19:14:01
Also in: linux-arm-kernel, lkml

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 <redacted>
---
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

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