[systemd-devel] udev-rules not applied to device

[Satz Klauer]

So...hopefully this is really the udev mailing list...

I use CentoOS 6.5, an embedded device that is connected via USB and
shows up as /dev/ttyACMx (in my case it is always /dev/ttyACM0). To
have it read/writable for everybody and to avoid the modem-manager is
accessing it I created following rule in
/etc/udev/rules.d/52-mydev.rules:

SUBSYSTEM=="usb", ATTR{idVendor}=="1781", ATTR{idProduct}=="1ef0",
MODE="0666", GROUP="plugdev", ENV{ID_MM_DEVICE_IGNORE}="1"

Unfortunately they are not working as expected, /dev/ttyACM0 is still
not world-read/writable and the modem-manager still comes in between.

What I found meanwhile using udev-debug-output: the rule is used and
applied, at least for the mode 0666. But udev sets the permissions to
the USB endpoint path (something with /bus/usb/...) but not to the
device.

So: how can I let udev change the permission of the device? And whyt
could be the reason why modem-manager still tries to use it?

Any ideas and suggestions are welcome!