USB Device # incrementing

[jsharrad]

Is there a way to stop the device # of a USB device from incrementing every time the device resets?

[mjbjr]

You can never be sure what /dev/xx a device will be assigned, particularly with usb.
You can resolve this type of issue by abstraction using a custom udev rule.

Sort of like saying:

if you see a usb device that has a model name of abc and a serial number of xyz make the device /dev/my_usb_camera.

With that kind of rule, that specific device, if it exists, will always be assigned to /dev/my_usb_camera
in addition to whatever /dev/xxx the system assigns it.

Yes, you can have mulktiple /dev's pointing to the same device.

Then you use /dev/my_usb_camera in your mounts, scripts, etc., because it will always "point" to the proper device.

Here are a couple of examples of my udev rules:

Note: in typical programming language convention,
"=" means assignment (c = 4)
"==" means test (does c == 4 ?)

BUS=="usb", SYSFS{product}=="Palm Handheld", NAME="%k", SYMLINK="treo", GROUP="uucp", MODE="0666"

in udev rules, typically,

the "NAME" parameter is the dev the kernel (notice the '%k') assigns and is subject to change
the "SYMLINK" parameter is what you want to *always* assign that particular device to... in the above udev creates /dev/treo

'/dev/treo' is what I use for the device to be accessed in my applications that need to communicate with the phone.

.
here's another example where you have two of the same devices and use the serial number to distinguish between them:
.

# ***** my personal Kingston Traveller USB Memory Stick ***** **********************************
BUS=="usb", SYSFS{manufacturer}=="Kingston", SYSFS{serial}=="5B680F8C74CE", NAME="%k", SYMLINK="my_kingston", MODE="0777"


# ***** my work data Kingston Traveller USB Memory Stick ***** **********************************
BUS=="usb", SYSFS{manufacturer}=="Kingston", SYSFS{serial}=="5B680F8C75GF", NAME="%k", SYMLINK="work_kingston", MODE="0777"

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for more info see:

http://www.gentoo.org/doc/en/udev-guide.xml

and there's another link at the bottom of that article
.
.

[Mgiese]

hi there, i use udev-115-r1, i got some problems using your command line :