Re: MtxOrb device

2014/1/21 Dave Platt <[email protected]>:
>
>>> 1. Is it possible to assign a fixed device instead of "/dev/ttyUSB0"?
>>
>> You might want to read a bit on udev. It can rename devices based on
>> rules. This way, you can access the display via /dev/MtxOrb or whatever
>> you prefer.
>
> Yup.  It's quite useful.
>
> The trickiest part is figuring out which attributes of the device (or
> its controller) to use for matching in the udev rule.  The documentation
> of the necessary lore isn't all that straightforward or easy to find.
>
> Here's a way to go about it.
>
> With the device plugged in, chant
>
>         udevadm info --name=/dev/ttyUSB0 --attribute-walk
>
> Look at what it tells you.
>
> What you'll need to do, most commonly, is pick a set of one or more of
> the ATTRS{} entries which uniquely identifies this particular device.
> If you need to use more than one ATTRS{} entry to distinguish this
> device from others on your system, you have to choose *all* of the
> ATTRS{} from the same level of "parent" (you can't combine ATTRS{}
> entries from different parents in a single rule).
>
> If you've got only one device from a particular manufacturer on your
> system, the problem is a fairly simple one... use the ATTRS{idVendor}.
> If you've got two or more device from the same manufacturer, but they're
> of different types, use ATTRS{idVendor} and ATTRS{idProduct} together.
>
> The tricky part is if you have two or more devices of the same type and
> manufacturer, and they don't include unique device serial numbers (the
> Prolofic PL2303 USB-to-serial chips and their clones are a common case
> of this).  In this case you may have to look for some obscure attribute
> which is different between them and is predictable (turns out to be the
> same on each reboot), such as the bus number, quirks, or ???.
>
> Put the necessary ruleset in a file in /etc/udev/rules.d/?????.conf - I
> recommend matching the attributes, and then using the "SYMLINK+="
> feature to add a symbolic link from the name you want, to the underlying
> device.
>
> Here's what I have as a ruleset for one such adapter, as
> /etc/udev/rules.d/x10.conf
>
> # Prolific USB-to-serial adapter, driving the X10 interface.
> # Unfortunately most Prolific devices have no serial number and are not
> individually
> # identifiable.
> SUBSYSTEM=="tty", ATTRS{idVendor}=="067b", ATTRS{idProduct}=="2303",
> SYMLINK+="x10", RUN+="/bin/stty -F /dev/%k clocal -crtscts -ixon -ixoff
> hupcl"
>
> This creates a /dev/x10 symlink to /dev/ttyUSB???, and also runs a
> command when the device is recognized.
>
> Here's one I use for an FTDI USB-to-serial adapter... it matches the
> vendor, product, and serial-number attributes.  With this approach, I
> could install any number of FTDI adapters of the same model, and be
> confident that each would be given the correct symbolic name... each
> device has a guaranteed-unique serial number to match against.
>
> SUBSYSTEM=="tty", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001",
> ATTRS{serial}=="FTQ8RNAJ", SYMLINK+="tnc", RUN+="/bin/stty -F /dev/%k
> clocal -crtscts -ixon -ixoff hupcl"
>
>
>
>
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Thanks both for your replys,

I try to fix the device with udev. This is the output of "udevadm info
--name=/dev/ttyUSB0 --attribute-walk": http://paste.debian.net/77762/

I create this file:

/etc/udev/rules.d/lcd.conf

With this content:

SUBSYSTEM=="tty", ATTRS{idVendor}=="1b3d", ATTRS{idProduct}=="0127",
SYMLINK+="lcd"

Change permissions:

chmod +x /etc/udev/rules.d/lcd.conf

When I reboot the PC, I can't get the "/dev/lcd" device. I am doing
something wrong?

Thanks for youe help.

Regards.

-- 
Josu Lazkano