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Solaris 8 System Administration Supplement

USB Overview

This overview is revised in the Solaris 8 1/01 software release.

Universal Serial Bus (USB) was developed by the PC industry to provide a low-cost solution for attaching peripheral devices, such as keyboards, mouse devices, and printers, to a system.

USB connectors are designed to fit only one type of cable, one way. Devices can connect to hub devices, which connect several devices, including other hub devices. The primary design motivation for USB is to alleviate the need for multiple connector types for different devices, thereby reducing the clutter on the back panel of a system. Additional advantages of using USB devices are:

Sun Microsystems support for USB devices includes the following:

This table provides a listing of specific USB devices that are supported in the Solaris environment.

These USB Devices ... 

Are Supported on These Systems ... 

Keyboards and mouse devices 

SPARC systems with Sun USB support based on the ohci(7D) controller

IA systems with a USB bus based on the uhci(7D) controller

Only onboard USB controllers are supported. Plug-in host controller PCI cards are not supported. 

Mass storage  

SPARC and IA 

Printers 

SPARC 

Hub 

SPARC and IA 

Commonly Used USB Acronyms

The following table describes the USB acronyms that are used in the Solaris environment. See http://www.usb.org for a complete description of USB components and acronyms.

Acronym  

Definition 

USB 

Universal Serial Bus 

USBA 

Universal Serial Bus Architecture (Solaris) 

USBAI 

USBA Client Driver Interface (Solaris) 

HCD 

USB host controller driver 

USB Bus Description

The USB specification, free of royalties, and openly available. The specification defines the electrical and mechanical interfaces of the bus and the connectors.

Figure 7-1 USB Physical Device Hierarchy

Graphic

USB employs a topology in which hubs provide attachment points for USB devices. The host controller contains the root hub, which is the origin of all USB ports in the system. See "USB Host Controller and Root Hub" for more information about hubs.

The previous example shows a system with three active USB ports. The first USB port has a Zip drive that does not have an embedded hub, so you cannot attach additional devices. The second USB port has a hub with a Jaz drive and a composite keyboard/mouse device connected. One of the ports from the secondary hub has a keyboard with an embedded hub where the mouse is attached.

The device tree path name for some of the devices displayed in the previous example are listed in this table.

Zip drive 

/pci@1f,4000/usb@5/storage@1

Keyboard 

/pci@1f,4000/usb@5/hub@2/keyboard@1

Mouse 

/pci@1f,4000/usb@5/hub@2/mouse@2

Jaz Drive 

/pci@1f,4000/usb@5/hub@2/storage@3

Printer 

/pci@1f,4000/usb@5/hub@3/printer@1

USB Devices and Drivers

The USB devices are divided into device classes. Each device class has a corresponding driver. Devices within a class are managed by the same device driver. However, the USB specification also allows for vendor-specific devices that are not part of a specific class. Devices with similar attributes and services are grouped.

The Human Interface Device (HID) class contains devices that are user controlled such as keyboards, mouse devices, and joysticks. The Communication Device class contains devices that connect to a telephone, such as modems or an ISDN interface. Other device classes include the Audio, Monitor, Printer, and Storage Device classes. Each USB device contains descriptors that reflect the class of the device. A device class specifies how its members should behave with respect to configuration and data transfer. You can obtain additional class information from the http://www.usb.org site.

Solaris USB Architecture (USBA)

USB devices are represented as two levels of device tree nodes. A device node represents the entire USB device and one or more child interface nodes represent the individual USB interfaces on the device. For special cases, the device and interface nodes are combined into a single combined node.

Driver binding is achieved by using the compatible name properties. Refer to 3.2.2.1 of the IEEE 1275 USB binding and the Writing Device Drivers for more information. A driver can either bind to the entire device and control all the interfaces, or a driver can bind to just one interface, for example, a keyboard or mouse. If no vendor or class driver claims the entire device, a generic USB multi-interface driver is bound to the device level node. This driver attempts to bind drivers to each interface using compatible names properties defined in section 3.3.2.1 of the 1275 binding.

Figure 7-1 shows an example of a hub and printer as a compound device. Both the hub and the printer are enclosed in the same plastic case, but the hub and the printer have separate USB bus addresses. The same diagram shows an example of a composite device. The composite keyboard and controller are also enclosed in the same plastic case, but they have the same USB bus address. A cable connects the USB mouse to the composite keyboard/controller in this example.

The Solaris USB Architecture (USBA) adheres to the USB 1.0 and 1.1 specification plus Solaris driver requirements. The USBA model is similar to Sun Common SCSI Architecture (SCSA). The USBA is a thin layer that provides a generic USB transport layer abstraction to the client driver.

The differences between SCSA and USBA are that the SCSA relies on .conf files to probe the bus, while USB hub drivers are self-probing nexus drivers.

About USB in the Solaris Environment

The following section describes 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 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.

Managing USB Mass Storage Devices With vold Running

If you are running Solaris Common Desktop Environment (CDE), the USB removable mass storage devices are managed by the Removable Media Manager component of the CDE File Manager. See dtfile(1) for more information on the CDE File Manager.

Note -

You must include the /usr/dt/man in your MANPATH variable to display the man pages listed in this section. You must also have /usr/dt/bin in your path and have CDE running to use these commands, or have a DISPLAY variable set to use these commands remotely.

The following table identifies the commands Removable Media Manager uses to manage storage devices from the CDE environment.

Command  

Task 

sdtmedia_format(1)

Format and label USB devices 

sdtmedia_prop(1)

Display properties of the device  

sdtmedia_prot(1)

Change device protection 

sdtmedia_slice(1)

Create or modify slices on the device  

After the USB device is formatted, it is usually mounted under the /rmdisk/label directory. See rmmount.conf(4) or vold.conf(4) for details on how to configure removable storage devices.

The following procedures describe how to manage USB mass storage devices with volume management. The device nodes are created under the /vol/dev directory. See scsa2usb(7D) for more information. The following procedures also describe how to add or remove hot-pluggable USB mass storage devices. Hot-plugging a device means the device is added or removed without shutting down the operating system or powering off the system.

How to Mount or Unmount a USB Mass Storage Device With vold Running

  1. Display device aliases for all removable mass storage devices, including USB mass storage devices.


    $ eject -n
.
.
.
rmdisk0 -> /vol/dev/rdsk/c4t0d0/clik40    (Generic USB storage)
cdrom0 -> /vol/dev/rdsk/c0t6d0/audio_cd   (Generic CD device)
zip1 -> /vol/dev/rdsk/c2t0d0/fat32        (USB Zip device)
zip0 -> /vol/dev/rdsk/c1t0d0/zip100       (USB Zip device)
jaz0 -> /vol/dev/rdsk/c3t0d0/jaz1gb       (USB Jaz device)

  2. Mount a USB mass storage device by using the device aliases listed previously.


    $ volrmmount -i device-alias

    This example mounts a USB Jaz drive under /rmdisk/jaz0.


    $ volrmmount -i jaz0

  3. Unmount a USB mass storage device.


    $ volrmmount -e device-alias

    This example unmounts a USB Zip drive from /rmdisk/zip0.


    $ volrmmount -e zip0

  4. Eject a USB device from a generic USB drive.


    $ eject device-alias

    For example:


    $ eject rmdisk0
    Note -

    The eject command also unmounts the device, if it is not unmounted already. The command also terminates any active applications that access the device.

How to Remove a Hot-Pluggable USB Mass Storage Device With vold Running

The following procedure uses a Zip drive as an example of removing a hot-pluggable USB device with vold running.

  1. Unmount the device.


    $ volrmmount -e zip0

  2. (Optional) Stop any active applications that are using the device.

  3. Eject the device.


    $ eject zip0

  4. Become superuser and stop vold.


    # /etc/init.d/volmgt stop

  5. Remove the USB mass storage device.

  6. Start vold.


    # /etc/init.d/volmgt start

How to Add a Hot-Pluggable USB Mass Storage Device With vold Running

This procedure describes how to add a hot-pluggable USB device with vold running.

  1. Insert the USB mass storage device.

  2. Restart vold.


    # pkill -HUP vold

  3. Verify the device has been added.


    $ ls device-alias

Managing USB Mass Storage Devices Without vold Running

You can use USB mass storage devices without the volume manager (vold) running. Here are two ways to avoid using the volume manager.

  1. Stop vold by issuing this command.


    # /etc/init.d/volmgt stop

  2. Keep vold running, but do not register the USB mass storage devices with it. Remove volume manager registration of USB mass storage devices by commenting the following line in the /etc/vold.conf file, like this:


    # use rmdisk drive /dev/rdsk/c*s2 dev_rmdisk.so rmdisk%d

    Once this line is commented, restart vold.


    # pkill -HUP vold_pid
    Caution - Caution -

    If you comment out this line and there are other SCSI or ATAPI Zip or Jaz removable devices in the system, vold registration for these devices would be disabled as well.

    See vold.conf(4) for details.

The following procedures describe how to manage USB mass storage devices without vold(1M) running. The device nodes are created under the /dev/rdsk directory for character devices and under the /dev/dsk directory for block devices. See scsa2usb(7D) for details.

How to Mount or Unmount a USB Mass Storage Device Without vold Running

  1. Become superuser.

  2. Mount a USB mass storage device. 


    # mount -F fs-type /dev/rdsk/cntndnsn /mount-point

  3. Unmount a USB mass storage device.


    # umount /mount-point

  4. Eject the device.


    # eject /dev/[r]dsk/cntndnsn

How to Remove a Hot-Pluggable USB Mass Storage Device Without vold Running

This procedure describes how to remove a hot-pluggable USB device without vold running.

  1. Become superuser.

  2. Remove the hot-pluggable USB device.

    1. Unmount the device. 


      # umount /mount-point

    2. (Optional) Stop any active applications that are using the device.

    3. Remove the device.

How to Add a Hot-Pluggable USB Mass Storage Device Without vold Running

This procedure describes how to add a hot-pluggable USB device without vold running.

  1. Add a hot-pluggable USB device into the USB port.

  2. Verify the USB device has been added.


    $ ls /dev/rdsk/cntndnsn

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 involves the hub driver to suspend 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 wake up 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. Avoid cascading many hubs to achieve the most efficient power management.

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.