Comment # 106 on bug 76490 from samdenies@zhentarim.net

(In reply to Alex Deucher from comment #105)
> Does this attached patch help?

I was not able to apply the patch itself as it didn't match the source for
4.5.1 that I downloaded.  However, adding the line manually did fix my problem.
 I am able to boot without radeon.dpm=0 and have good 3d performance.  Thanks!