USB Administration Guide

About USB in the Solaris Environment

The following sections describe specific information you should know about USB in the Solaris environment.

USB Keyboards and Mouse Devices

Keep only one USB keyboard and mouse on the system at all times because multiple USB keyboards and mouse devices are not supported in the Solaris environment. See the following items for specific details.

USB Host Controller and Root Hub

A USB hub is responsible for:

The USB host controller has an embedded hub called the root hub. The ports that are visible at the back panel are the ports of the root hub. The USB host controller is responsible for:

USB Hub Devices

USB Storage Devices

Removable mass storage devices such as USB Zip, Jaz, Clik!, SmartMedia, CompactFlash, and ORB are supported, starting with the Solaris 8 10/00 release. See scsa2usb(7D) for a complete list of devices that are supported in the Solaris environment.

These devices can be managed with or without volume management. See vold(1M) for information on managing devices with volume management.

SPARC Only: USB Power Management

If the system has enabled power management, the USB framework makes a best effort to power-manage all devices. Power-managing a USB device means the hub driver suspends the port to which the device is connected. The device might or might not support remote wakeup. If the device supports remote wakeup, it wakes up the hub it is connected to, depending on the event, such as moving the mouse. The host system could also wake the device if an application sends an I/O to it.

All HID (keyboard, mouse, and so forth), hub, and storage devices are power-managed by default if they support the remote wakeup capability. A USB printer is power-managed only between two print jobs.

When you power-manage to reduce power consumption, USB leaf devices are powered down first, and after some delay, the parent hub is powered down. When all devices that are connected to this hub's ports are powered down, the hub is powered down after some delay. To achieve the most efficient power management, do not cascade many hubs.

Hot-Plugging USB Devices

When you plug in a USB device, the device is immediately seen in the system's device hierarchy, as displayed in the prtconf(1M) command output. When you remove a USB device, the device is removed from the system's device hierarchy, unless the device is in use.

If the USB device is in use when it is removed, the hot-plug behavior is a little different. If a device is in use when it is unplugged, the device node remains, but the driver controlling this device stops all activity on the device. Any new I/O activity issued to this device is returned with an error.

In this situation, the system prompts you to plug in the original device. To recover from accidentally removing a busy USB device, do the following:

  1. Plug the original device into the same port.

  2. Stop the application that is using the device.

  3. Remove the device.

The USB port remains unusable until the original device has been plugged in again. If the device is no longer available, the port remains unusable until the next reboot.

Note –

Data integrity might be impaired if you remove an active or open device. Always close the device before removing, except the console keyboard and mouse, which can be moved while active.

USB Cables

Never use USB cable extenders that are available in the market. Always use a hub with longer cables to connect devices. Always use fully rated (12 Mbit/sec) 20/28 AWG cables for connecting USB devices.