Re: How the EHCI HC driver make the decision to suspend some USB devices?

[Alan Stern]

On Fri, 19 Aug 2016, ludeng wrote:

> Hi,
> How the EHCI HC driver make the decision to suspend some USB devices,
> but not to suspend some others? We notice that for some USB Video
> Cameras, when they are enumerated and there is no data to transfer,
> the EHCI HC driver will suspend them by setting the Suspend bit of
> the PORTSC register. But for some other Cameras, the EHCI HC driver
> will not suspend them. The drvier make the decision based on what
> kind of information of the device ?

The EHCI driver does not make this decision.  The decision is made by 
the video camera driver and by the user.

Alan Stern