Why do we try to enter U1 mode in SuperSpeed?

[Hans Petter Selasky]

On 03/30/15 11:36, Kohji Okuno wrote:
> Hi HPS,
>
>
> I will try programming values 0xFF.
> By the way, why should we set these timeout value?
> I think, we don't have to change from default values (U1 Timeout = 0,
> U2 Timeout= 0).

Hi,

I think the default '0' is the same like '255' - disable power save? 
Where is the meaning of "default" defined in this case?

In the USB v3.0 specification it says that we shall not enable the U2 
timeout for a downstream port that is connected to a HUB. Currently 
there is no check for that. We might want to add such a check.

--HPS