Loss of USB device access under Linux - IBM eServer BladeCenter JS20

Resolving The Problem

RETAIN tip: H181973

• USB attached storage devices may lose connection when used in a BladeCenter.
• A Management Module reset or fail-over may occur during or prior to the loss of connection.
• Under Linux, USB storage devices that are disconnected do not reappear as the same device.
• For example, if on boot the floppy is discovered as /dev/sda, and the CD-ROM is discovered as /dev/sdb, a disconnect will be processed as a hotplug event, and two new devices will be created, /dev/sdc and /dev/sdd.
• The previous device names will still exist, but there is no way to access them.
• To access the devices, you must use the current names.

The system may be any model of the IBM eServer BladeCenter JS20, Type 8842.

If the USB attached storage devices lose connection, you will have to remount the devices before using them. The previous device names will still exist, but there is no way to access them. To access the devices, you must use the current names. Run the lsmod command, and make a note of all modules with "usb" in the name.

For example:

bc1-173# lsmod
Module Size Used Not
By Tainted

usb-storage 101656 0
ipv6 482184 -1 (autoclean)
key 102888 0 (autoclean) ipv6
mousedev 9968 0 (unused)
keybdev 4920 0 (unused)
joydev 13088 0 (unused)
evdev 10248 0 (unused)
input 10648 0 mousedev keybdev joydev evdev
usb-ohci 36768 0 (unused)
usbcore 133664 1 usb-storage usb-ohci
bcm5700 197816 1
lvm-mod 110888 0 (autoclean)

Use the rmmod command to unload the drivers.

For example:

rmmod usb-storage
rmmod usb-ohci
rmmod usbstorage

Then use the modprobe command to reload all the modules:

modprobe usb-storage

This is currently an architectural limitation.