[argyllcms] Re: argyll v0.60.2 usb assignments

Caspar Maessen wrote:
A lot of trail and error later, I found out that it is possible with a udev-rule to change the owner/group assignment of the device as it is made by the system in the /dev/bus/usb subdirectories
BUS="usb", SYSFS{idVendor}="0765", SYSFS{idProduct}="d094", OWNER="caspar", GROUP="users"
So, no NAME="%k" argument, because that is creating a new device under /dev/ and none under /bus/usb/ and basically that is causing the problem. The MODE="%k" argument doesn't work on the system-created device. Looking for a solution I found the OWNER-argument, and that solved it. 

The more I look into it, the less I can figure out. I'm not sure
what I see on my system is unique to it, or can be generalized to
other systems. It seems to have hotplug, and udev doesn't seem to
work regarding usb devices. Whether this is because of a bug in udev,
or because hotplug is present, I don't know.

This <http://www.mail-archive.com/avr-chat@xxxxxxxxxx/msg00902.html>
indicates that libusb will look for usb devices both under
/proc/bus/usb/... as well as /dev/bus/usb/..., so it's unclear
why you had a problem. The above reference, as well as
<http://reactivated.net/writing_udev_rules.html> uses the
"==" syntax in the udev config files (ie. SUBSYSTEM=="usb_device"),
which whenever I used them, triggered problems (judging by the
log files from udev, or output from udevtest). The examples in
"man udev" seem to only a single "=" for matching conditions, which
is a rather strange disagreement.

Your changes didn't work on my system :-(

Graeme Gill.

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