permissions on /dev/nvidia*

["Giorgio Ruffa" <giorgio_ruffa@pcteor1.mi.infn.it>]

Hi all and thanks for reading,
I have a messy problem of permissions of /dev/nvidiactl and /dev/nvidia0.
As usual on debian distributions the video devices are owned by the video group.

ls -l /dev/nvidia*
crw-rw---- 1 root video 195,   0 Sep 27 17:56 /dev/nvidia0
crw-rw---- 1 root video 195, 255 Sep 27 17:56 /dev/nvidiactl

The problem is that I have a cluster with 1600 users and we use an ldap server for autentication where groups are not implemented (unfortunately i have no access to the LDAP server);
so all the users belong to the group users and I can't add all of them to the video group so users cannot open the nvidia* devices.

to solve the problem i tried to edit the init.d/nvidia-kernel script and replaced the line 
	mknod -m 0660 dev/nvidiactl c 195 255
with
	mknod -m 0666 dev/nvidiactl c 195 256

and editing /etc/modprobe.d/nvidia-kernel-nkc.conf  as suggested here: http://forums.nvidia.com/index.php?showtopic=82687

After the system boot permissions ore ok, but they are changed to default values after starting X or every application which tries to access these devices ; 

I've also edited /etc/udev/rules.d/061_nvidia.rules (wich is a symlink to /etc/udev/nvidia.rules) adding the line 
SUBSYSTEM=="nvidia*",				GROUP="users" , MODE="0666"
and even
KERNEL=="nvidia*",	NAME="%k"	,		GROUP="users" , MODE="0666"

but this doesn't solve the problem.

I've found nothing about video devices looking into consolekit or policykit conf files.

Do you know which program is responsible for the automatic changes of devices permissions?

Best regards


-- 
	
		Giorgio Ruffa