SPARC: USB 2.0 Features (System Administration Guide: Devices and File Systems)

System Administration Guide: Devices and File Systems

SPARC: USB 2.0 Features

This Solaris release includes the following USB 2.0 features:

Better performance – Increased data throughput for devices connected to USB 2.0 controllers, up to 40 times faster than USB 1.1 devices.

You will be able to take advantage of the high-speed USB protocol when accessing high-speed mass storage devices, such as DVDs and hard drives.
Compatibility – Backward compatibility with 1.0 and 1.1 devices and drivers so that you can use the same cables, connectors, and software interfaces.

For a description of USB devices and terminology, see Overview of USB Devices.

USB 2.0 Device Features and Compatibility Issues

USB 2.0 devices are defined as high-speed devices that follow the USB 2.0 specification. You can refer to the USB 2.0 specification at http://www.usb.org.

Some of the USB devices that are supported on SPARC based and x86 based systems in this Solaris release are as follows:

Mass storage devices – CD-RWs, hard disks, DVD, digital cameras, Zip, diskettes, and tape drives
Keyboard, mouse devices, speakers and microphones
Audio devices

For a full listing of USB devices that have been verified on the Solaris release, go to:

http://www.sun.com/io_technologies/usb.html

Additional storage devices might work by modifying the scsa2usb.conf file. For more information, see the scsa2usb(7D) man page.

Solaris USB 2.0 device support includes the following features:

Increased USB bus speed from 12 Mbps to 480 Mbps. This increase means devices that support the USB 2.0 specification can run significantly faster than their USB 1.1 counterparts, when they are connected to a USB 2.0 port.

A USB 2.0 port is defined on SPARC systems as follows:
- A port on a USB 2.0 PCI card
- A port on a USB 2.0 hub that is connected to USB 2.0 port
USB 2.0 is Solaris Ready on all PCI-based SPARC platforms. A USB 2.0 PCI card is needed to provide USB 2.0 ports. For a list of USB 2.0 PCI cards that have been verified for the Solaris release, go to http://www.sun.com/io_technologies/usb.html.
USB 1.1 devices work as they have in the past, even if you have both USB 1.1 and USB 2.0 devices on the same system.
While USB 2.0 devices operate on a USB 1.x port, their performance is significantly better when connected to a USB 2.0 port.
A USB 2.0 host controller has one high-speed Enhanced Host Controller (EHCI) and one or more low- or full-speed OpenHCI Host Controller (OHCI) embedded controllers. Devices connected to a USB 2.0 port are dynamically assigned to either an EHCI or OHCI controller, depending on whether or not they support USB 2.0.

Note –
USB 2.0 storage devices connected to a port on a USB 2.0 PCI card, and that were used with a prior Solaris release in the same hardware configuration, can change device names after upgrading to this release. This change occurs because these devices are now seen as USB 2.0 devices and are taken over by the EHCI controller. The controller number, w in /dev/[r]dsk/cwtxdysz, is changed for these devices.

For more information on USB 2.0 device support, see the ehci(7D) and usba(7D) man pages.

USB 2.0 Cables

Maximum cable length supported is 5 meters.
Do not use cable extenders. For best results, use a self-powered hub to extend cable length.
For more information, go to http://www.usb.org/channel/training/warning/

Bus-Powered Devices

Bus-powered hubs use power from the USB bus to which they are connected, to power devices connected to them. Special care must be taken to not overload these hubs, since the power these hubs offer to their downstream devices is limited.

Do not cascade bus-powered hubs. For example, do not connect one bus-powered hub to another bus-powered hub.
Avoid connecting bus-powered devices to bus-powered hubs, except for low-speed, low-power devices, such as keyboards or mice. Connecting high-powered devices such as disks, speakers, or microphones to a bus-powered hub could cause power-shortages for all devices connected to that hub. This scenario could cause these devices to behave unpredictably.