Hi
It's the "Dell Renesas USB 3.0 Host Controller". I'm not positive if it's a motherboard or USB driver. Yes, this was an upgrade.
Just wanted to see if they had any updates dealing with USB. Hope this helps.
http://www.dell.com/support/drivers/us/en/19/DriverDetails/DriverFileFormats?DriverId=61X2W&FileId=2907012265&productCode=xps-l502x&urlProductCode=False