FAQ

1.Why does my O6 / O6N have high memory usage after booting?

System reserves a part of memory for NPU to ensure NPU works properly, so the available memory looks like short.

Temporarily disable NPU (restores after reboot):

Linux$

sudo rmmod aipu

Permanently disable NPU (blacklist):

Linux$

sudo vim /etc/modprobe.d/blacklist-aipu.conf

Add:

Linux$

blacklist aipu

Save and reboot:

Linux$

sudo reboot

Note: Disabling will free the memory reserved for NPU. To restore, delete the blacklist configuration and reboot.

2.Orion O6 USB3 Bulk Transfer Causes Device Disconnect/Re-enumeration

When using USB3 devices like Cypress FX3 (VID:PID 04b4:00f1) for high-throughput bulk transfers, Orion O6 may experience device disconnection and re-enumeration.

Symptoms

• Device disconnects and re-enumerates during sustained high-throughput USB bulk transfers
• Error: LIBUSB_ERROR_NO_DEVICE
• dmesg shows: usb 6-1: USB disconnect, device number 3 → usb 6-1: new SuperSpeed USB device number 4 using xhci-hcd

Possible Causes

1. Insufficient Power Supply: USB3.2 Type-A ports have a 1A current limit, high-power devices may exceed this limit
2. Cable Quality: Poor quality or excessively long USB3 cables may cause signal integrity issues
3. xHCI Driver/Firmware Issues: xHCI controller may exhibit stability issues under high load
4. USB3 Link Management: USB3 link power management (U1/U2 states) may cause instability

Troubleshooting Steps

1. Check Power Supply:
   • Use a dedicated 12V/3A or higher power adapter
   • Avoid powering high-power devices through USB hubs
2. Replace Cables and Ports:
   • Use high-quality, short-length USB3 cables
   • Try different USB3.2 Type-A ports
3. Check System Logs:

   dmesg | grep -i "usb\|xhci"
   journalctl -k | grep -i "usb\|xhci"

4. Disable USB Autosuspend and Link Power Management:

   # Temporarily disable USB autosuspend
   for dev in /sys/bus/usb/devices/*/power/control; do
     echo on > "$dev" 2>/dev/null || true
   done
   
   # Disable USB3 link power management (add to boot parameters)
   # Add to the append line in /boot/extlinux/extlinux.conf:
   # usbcore.autosuspend=-1 usbcore.quirks=vid:pid:u

Solutions

1. Use Externally Powered USB3 Hub: Provide independent power for high-power USB3 devices
2. Update BIOS and Kernel: Check for available BIOS updates or kernel patches
3. Adjust Transfer Parameters: Reduce data rate for bulk transfers or use smaller packets
4. Contact Technical Support: If the issue persists, contact Radxa technical support with detailed system logs

Known Compatibility Issues

• Cypress FX3 (VID:PID 04b4:00f1) may experience this issue during high-throughput bulk transfers
• Some USB3 storage devices may trigger disconnect/re-enumeration during sustained write operations

Note: This issue may be specific to certain hardware combinations. It's recommended to verify compatibility with Orion O6 before purchasing USB3 peripherals.