CYUSB4357 Suspend Behavior

[can2021]

Does the CYUSB4357 Hub support Selective Suspend between the USB2 and USB3 channels?  That is, are the active and suspend states of both USB2 and USB3 channels in the Hub treated together?   

Case: If the Hubs upstream USB3 link is inactive but the USB2 link is active, and the host decides to put the USB3 link to sleep, will the USB2 link in the Hub stay in an active mode, or will the Hub keep the USB3 link up because the USB2 link is active.  Visa-versa, if the Hubs upstream USB2 link is inactive and the USB3 link is active, and the host wants to put the USB2 link to sleep, will the USB3 link stay up, or will it also go into suspend mode, or will the Hub keep both links up because of the activity on the USB3 link?  

Finally,  I assume that if the Hub can treat the USB2 and USB3 link states separately, that it can also support putting the respective downstream ports to suspend state depending if the downstream ports are connected to USB2 or USB3 endpoints.  Is that correct?   

[MallikaK_22 · Accepted solution]

Hi,

Yes, it is correct, HX3PD can put selected ports into suspend state. So even a USB 2.0 port can be put into suspend state while the other USB 3.0 port is functional.

[can2021]

Thanks.  So, can the hub indicate via a GPIO when the upstream USB3 port has gone into suspend, and ignore the state of the USB2 link, or separately signal via a separate GPIO when the upstream USB2 port has gone into suspend?