How to Change the Default Configuration of a Multi-Configuration USB Device

Keep the following in mind when working with multi-configuration USB devices:

• A USB device configuration defines how a device presents itself to the operating system. This method is different from system device configurations discussed in other cfgadm sections.

• Some USB devices support multiple configurations, but only one configuration can be active at a time.

• Multi-configuration devices can be identified by examining the cfgadm -lv output. Nconfigs will be greater than 1.

• The default USB configuration is configuration 1. The current configuration is reflected in cfgadm -lv output as Config.

• Changes to the default configuration persist across reboots, hot-removes, and the reconfiguration of the device, as long as the device is reconnected to the same port.

1. Make sure that the device is not in use.

2. Change the default USB configuration.

   For example:

   # cfgadm -x usb_config -o config=2 usb0/4 Setting the device: /devices/pci@1f,0/usb@c,3:4 to USB configuration 2 This operation will suspend activity on the USB device Continue (yes/no)? yes

3. Verify that the device changed.

   For example:

   # cfgadm -lv usb0/4 Ap_Id Receptacle Occupant Condition Information When Type Busy Phys_Id usb0/4 connected unconfigured ok Mfg: Sun 2000 Product: USB-B0B0 aka Robotech With 6 EPPS High Clk Mode NConfigs: 7 Config: 2 : EVAL Board Setup unavailable usb-device n /devices/pci@1f,0/usb@c,3:4

   Note that Config: now shows 2.