Description of problem:
SELinux is preventing /usr/bin/Xorg from 'write' accesses on the file mtrr.

*****  Plugin catchall (100. confidence) suggests  ***************************

If you believe that Xorg should be allowed write access on the mtrr file by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# grep Xorg /var/log/audit/audit.log | audit2allow -M mypol
# semodule -i mypol.pp

Additional Information:
Source Context                system_u:system_r:xdm_t:s0-s0:c0.c1023
Target Context                system_u:object_r:mtrr_device_t:s0
Target Objects                mtrr [ file ]
Source                        Xorg
Source Path                   /usr/bin/Xorg
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           xorg-x11-server-Xorg-1.13.2-1.fc18.i686
Target RPM Packages           
Policy RPM                    selinux-policy-3.11.1-73.fc18.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 3.7.4-204.fc18.i686 #1 SMP Wed Jan
                              23 17:08:59 UTC 2013 i686 i686
Alert Count                   2
First Seen                    2013-02-05 06:37:37 MSK
Last Seen                     2013-02-05 06:37:37 MSK
Local ID                      7eaf3e05-f67c-469a-9846-a7630378c336

Raw Audit Messages
type=AVC msg=audit(1360031857.210:171): avc:  denied  { write } for  pid=785 comm="Xorg" name="mtrr" dev="proc" ino=4026531957 scontext=system_u:system_r:xdm_t:s0-s0:c0.c1023 tcontext=system_u:object_r:mtrr_device_t:s0 tclass=file


type=SYSCALL msg=audit(1360031857.210:171): arch=i386 syscall=open success=no exit=EACCES a0=4dc8a1e7 a1=80001 a2=bfd3e7e4 a3=4dc8a154 items=0 ppid=770 pid=785 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 ses=4294967295 tty=(none) comm=Xorg exe=/usr/bin/Xorg subj=system_u:system_r:xdm_t:s0-s0:c0.c1023 key=(null)

Hash: Xorg,xdm_t,mtrr_device_t,file,write

audit2allow

#============= xdm_t ==============
allow xdm_t mtrr_device_t:file write;

audit2allow -R

#============= xdm_t ==============
allow xdm_t mtrr_device_t:file write;


Additional info:
hashmarkername: setroubleshoot
kernel:         3.7.4-204.fc18.i686
type:           libreport