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USB Ethernet adaptors

USB Ethernet adaptors are commonly available, and provide a simple way to add Ethernet to an STMicroelectronics system.
There are two main chip sets used; based on either an ASIX® chip or a Pegasus chip. Of these two, the ASIX is more common and offers better performance as it is USB2; Pegasus is the older USB1.

Enable the support for USB Ethernet adaptors

  • ASIX  AX88xxx (CONFIG_USB_AX8817X)
    Device Drivers ---> Network Device Support ---> USB Network Adapters ---> Multi-purpose USB Networking Framework ---> ASIX AX88xxx Based USB 2.0 Ethernet Devices
  • Pegasus/Pegasus-II (CONFIG_USB_PEGASUS)
    Device Drivers ---> Network Device Support ---> USB Network Adapters ---> USB Pegasus/Pegasus-II based ethernet device support
  • ASIX  AX88xxx (CONFIG_USB_AX8817X)
    Device Drivers ---> USB Support ---> USB Network Adapters ---> Multi-purpose USB Networking Framework ---> ASIX AX88xxx Based USB 2.0 Ethernet Devices
  • Pegasus/Pegasus-II (CONFIG_USB_PEGASUS)

    Device Drivers ---> USB Support ---> USB Network Adapters ---> USB Pegasus/Pegasus-II based ethernet device support

When the USB adaptor is plugged in, a message similar to this should appear:

eth1: register usbnet at usb-STB7100_ehci_bus-1.3, ASIX AX8817x USB 2.0 Ethernet

The network can be configured as any other network using ifconfig.

Using a USB Ethernet adaptor with an NFS root file system

It is possible to use USB Ethernet to access a root file system over NFS. However it takes a few seconds for the USB subsystem to identify the ethernet adaptor and make it ready for use. This happens asynchronously to the main kernel booting, so the kernel may try to configure the Ethernet device before the USB subsystem is ready. The solution to this is to pass a kernel command line option ipconfdelay=<sec>, where <sec> is the number of seconds to delay before attempting to configure the Ethernet adaptor.