The following was filed automatically by setroubleshoot:

Summary:

SELinux is preventing Xorg (xserver_t) "read" access to device /dev/vga_arbiter.

Detailed Description:

[SELinux is in permissive mode, the operation would have been denied but was
permitted due to permissive mode.]

SELinux has denied the Xorg (xserver_t) "read" access to device
/dev/vga_arbiter. /dev/vga_arbiter is mislabeled, this device has the default
label of the /dev directory, which should not happen. All Character and/or Block
Devices should have a label. You can attempt to change the label of the file
using restorecon -v '/dev/vga_arbiter'. If this device remains labeled device_t,
then this is a bug in SELinux policy. Please file a bug report
(http://bugzilla.redhat.com/bugzilla/enter_bug.cgi) against the selinux-policy
package. If you look at the other similar devices labels, ls -lZ /dev/SIMILAR,
and find a type that would work for /dev/vga_arbiter, you can use chcon -t
SIMILAR_TYPE '/dev/vga_arbiter', If this fixes the problem, you can make this
permanent by executing semanage fcontext -a -t SIMILAR_TYPE '/dev/vga_arbiter'
If the restorecon changes the context, this indicates that the application that
created the device, created it without using SELinux APIs. If you can figure out
which application created the device, please file a bug report
(http://bugzilla.redhat.com/bugzilla/enter_bug.cgi) against this application.

Allowing Access:

Attempt restorecon -v '/dev/vga_arbiter' or chcon -t SIMILAR_TYPE
'/dev/vga_arbiter'

Additional Information:

Source Context                system_u:system_r:xserver_t:s0-s0:c0.c1023
Target Context                system_u:object_r:device_t:s0
Target Objects                /dev/vga_arbiter [ chr_file ]
Source                        Xorg
Source Path                   /usr/bin/Xorg (deleted)
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           
Target RPM Packages           
Policy RPM                    selinux-policy-3.6.28-2.fc12
Selinux Enabled               True
Policy Type                   targeted
MLS Enabled                   True
Enforcing Mode                Enforcing
Plugin Name                   device
Host Name                     (removed)
Platform                      Linux (removed)
                              2.6.31-0.125.4.2.rc5.git2.fc12.i686.PAE #1 SMP Tue
                              Aug 11 21:01:03 EDT 2009 i686 i686
Alert Count                   2
First Seen                    Thu 20 Aug 2009 04:25:14 PM EDT
Last Seen                     Thu 20 Aug 2009 04:57:21 PM EDT
Local ID                      618ac11e-609f-4db0-8ad5-8f31bc81e784
Line Numbers                  

Raw Audit Messages            

node=(removed) type=AVC msg=audit(1250801841.774:24956): avc:  denied  { read } for  pid=1353 comm="Xorg" path="/dev/vga_arbiter" dev=tmpfs ino=1132 scontext=system_u:system_r:xserver_t:s0-s0:c0.c1023 tcontext=system_u:object_r:device_t:s0 tclass=chr_file

node=(removed) type=SYSCALL msg=audit(1250801841.774:24956): arch=40000003 syscall=3 success=yes exit=64 a0=8 a1=bf94cbfc a2=40 a3=85f4974 items=0 ppid=1352 pid=1353 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=tty1 ses=4294967295 comm="Xorg" exe=2F7573722F62696E2F586F7267202864656C6574656429 subj=system_u:system_r:xserver_t:s0-s0:c0.c1023 key=(null)


audit2allow suggests:

#============= xserver_t ==============
allow xserver_t device_t:chr_file read;