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Re: FC5 hotplug documentation?



Wolfgang S. Rupprecht wrote:
>>> BUS="usb", SYSFS{serial}="<serial number of GPS device>",
>>> NAME="gps", MODE="0666"
> 
> Thanks to everybody that helped flesh this out.  The key for me was
> knowing that hotplug is now spelled "udev" was key to finding some
> documentation.
> 
> One thing that wasn't clear was can I just make a file by the name
> /etc/udev/rules.d/10-local.rules and put my additions in there?  One
> of the udev doc files had a caution that one needed to duplicate some
> default settings if one made an "upstream" file.  It wasn't clear how
> to identify what needed duplication.
>  
> from Fc5 /usr/share/doc/udev-084/writing_udev_rules/index.html:
> 
>         As your own rules will effectively mask out the udev defaults
>         which create the base /dev layout, it is recommended that you
>         also specify devfs-style names/symlinks for the rules you
>         write, so that you get the sensible defaults plus your own
>         names.
> 
> I just don't follow what they are saying.
> 
Yes, you can create your own file. I believe what they are talking
about is that want to make sure your rules are ether specific to one
device, or if they match many devices, that they have the proper
syntax. For example, you would not want every USB serial port to end
up with the same device name and/or symlink. You also want to be
careful if you are matching on device type or manufacturer, that you
use a form that allows more then one device. The example they use is
NAME="camera%n" so that you get /dev/camera0, /dev/camera1, etc.

In the examples I gave you, there could be problems if you have more
then one GPS device plugged in at the same time. It would not be a
problem with using the serial number, unless you manage to get two
devices with the same serial number. For the second example, if you
expect to use more then one GPS device at the same time, change the
NAME="gps" to NAME="gps%n" and change your software to use /dev/gps0
instead of /dev/gps. If you run a second GPS, then the software
would have to use /dev/gps1 for the second GPS device...

Mikkel
-- 

  Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!


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