setting permissions when USB devices plugged in

wufo · 01-25-2010, 09:47 PM

When I plug in a USB GPS device, using cypress_m8 module, is creates
/dev/ttyUSB0 with read/write permissions for owner,root, and group, dialout. My question is really just where are the rules for setting these permissions and how exactly are the owner and group names set when /dev/ttyUSB0 is created, i.e. a serial USB device is plugged in.

wufo

quanta · 01-25-2010, 10:03 PM

Try to edit (or create) the /etc/udev/rules.d/*-libsane.rules file.

wufo · 01-26-2010, 09:27 AM

Quote:

Originally Posted by quanta

Try to edit (or create) the /etc/udev/rules.d/*-libsane.rules file.

This file does not exist. I checked /etc/udev/rules.d and neither of the two files:
70-persistent-cd.rules 70-persistent-net.rules

has a rule for USB serial.

So, how does system know what the default for ttyUSB0 is?

wufo

XGizzmo · 01-26-2010, 11:16 AM

The files are in /lib/udev/rules.d also the libsane stuff is for scanners. Do not edit the rules in /lib/udev copy the rule you want to edit to /etc/udev/rules.d and edit the copy.