Synchronous video reading from seven port USB3.0 HUB

I want to read synchronous image from seven port USB3.0 HUB connected to Jetson TX2. I have 7 cameras in total. The resolution of each of my cameras is 640x512. So the bandwidth is sufficient. Each port of the HUB supports 1.5A, so there should be no power problem. When I plug in the cameras and look under /dev, the cameras randomly sometimes see it, sometimes not. It seems that the file under /dev is not updated when I plug in the cable of each camera to the HUB. When jetson tx2 reboots, the cameras come on, but after a while, some cameras start to go. I made usbcore.autosuspend=-1 to avoid autosuspend error. The system seems to be a little more stable, but the problem persists. What could be the source of the problem?