Khadas VIM3 contains a 2:1 data switch chipset to switch the “combo interface” between PCIe and USB 3.0, and the default mode is USB 3.0.
You need to setup the serial debug tool and enter the u-boot command line.
Initialize the KBI:
kvim3#kbi init
Check current port mode:
kvim3#kbi portmode r port mode is USB3.0
The default mode is USB-3.0.
Change mode to PCIe:
kvim3#kbi portmode w 1 set port mode to :PCIE
Change mode to USB 3.0:
kvim3#kbi portmode w 0 set port mode to :USB3.0
Poweroff the system to bring changes into effect:
kvim3#kbi poweroff do_kbi_poweroff
Then press the POWER KEY to boot the system
Check current port mode:
khadas@Khadas:~$ cat /sys/class/mcu/usb_pcie_switch_mode
1
0 - USB 3.0 mode
1 - PCIe mode
Change mode to USB 3.0:
khadas@Khadas:~$ echo 0 > /sys/class/mcu/usb_pcie_switch_mode
Change mode to PCIe:
khadas@Khadas:~$ echo 1 > /sys/class/mcu/usb_pcie_switch_mode
Poweroff the system to bring changes into effect:
khadas@Khadas:~$ echo 1 > /sys/class/mcu/poweroff
Then press the POWER KEY to boot the system.