(In reply to Lin Ma from comment #9) > Could you please help to capture the trace data and upload it? lsusb -t (pre-start): > vmhost:~ # lsusb -t > /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/7p, 5000M > /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/9p, 480M > |__ Port 1: Dev 2, If 0, Class=Vendor Specific Class, Driver=ftdi_sio, 12M > |__ Port 3: Dev 3, If 0, Class=Communications, Driver=cdc_acm, 12M > |__ Port 3: Dev 3, If 1, Class=CDC Data, Driver=cdc_acm, 12M > |__ Port 4: Dev 4, If 0, Class=Vendor Specific Class, Driver=ftdi_sio, 12M Attached: /var/log/libvirt/qemu/USB_Test.log lsusb -t (post-resume): > vmhost:~ # lsusb -t > /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/7p, 5000M > /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/9p, 480M > |__ Port 1: Dev 2, If 0, Class=Vendor Specific Class, Driver=ftdi_sio, 12M > |__ Port 3: Dev 3, If 0, Class=Communications, Driver=cdc_acm, 12M > |__ Port 3: Dev 3, If 1, Class=CDC Data, Driver=cdc_acm, 12M > |__ Port 4: Dev 4, If 0, Class=Vendor Specific Class, Driver=ftdi_sio, 12M