USB Hub IC reset script

If you need to do power-cycle to the USB devices on the USB host ports, run below commands.
It will reset all the USB devices connected to the USB host ports.

echo 126 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio126/direction
sleep 1
echo 0 > /sys/class/gpio/gpio126/value
sleep 1
echo 1 > /sys/class/gpio/gpio126/value
echo 126 > /sys/class/gpio/unexport
sleep 1

USB Hub IC issue

Every power cycle, the USB hub controller is disconnecting the USB devices at among 5~7 second after starting the boot process.
If you use a fast booting OS like Buildroot, Yocto and Ubuntu-Minimal, your USB devices will not work correctly.
To avoid this issue, you need to run your USB application software slightly later after complete the booting process.

Here is an example of the serious problem. Unfortunately, we couldn't find any workaround yet.
Forum Thread

  • odroid-c2/troubleshooting/usb_hub_ic.txt
  • Last modified: 2017/06/30 18:11
  • by luke.go