I think I got the same problem

kernel 3.14.2-1 on arch linux.

lspci | egrep "VGA|3D|Display"
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
RV635/M86 [Mobility Radeon HD 3650]

$cat /etc/X11/xorg.conf.d/20-radeon.conf
Section "Device"
       Identifier  "My Graphics Card"
       Option "AccelMethod" "EXA"
       Option "EXAVSync" "yes"
EndSection

/var/log/Xorg.0.log = http://pastebin.com/dR2Vayr7

I'm opening DPM
and sometimes freezes the computer
alt + f2 does not respond

Is there a solution to this or the updates will solve this problem?
I want to use DPM
because perfected  performance
hopefully resolve