On 2021/3/4 9:35, Peter Chen wrote: > On 21-02-27 11:31:00, liulongfang wrote: >> On 2021/2/26 16:38, Greg KH wrote: >>> On Fri, Feb 26, 2021 at 04:21:37PM +0800, Longfang Liu wrote: >>>> Our current XHCI hardware controller has been customized to only >>>> support USB 2.0 ports. >>> >>> That sounds like a spec violation, right? Why do you want to do this? >>> >>> greg k-h >>> . >>> >> I hope to support a USB2.0-only mode on the XHCI controller >> through software configuration. >> Thanks. > > If your hardware has disabled USB3 logic, when the USB3 device is plugged, > since there are no RX signal on the bus, the device will not enable USB3 > logic, and only USB2 signals will be on the bus, there are only USB devices on > USB2 roothub later. So, any issues you have met? > I don’t want to see the USB3 bus controller in the system, but it actually exists. Thanks. Longfang, Liu
