(In reply to comment #33)
> > Here is a partial kernel.log tracking what is going on at boot with some
> > debug printk in evergreen_mc_stop() and evergreen_mc_resume(). Strangely,
> > only one crtc is saved as enabled in the _stop function, but four are
> > restored in the _resume function. Pretty sure it's not the problem we are
> > looking for, but it is abnormal since only one crtc should be restored on
> > resume. This is a bug by itself showing a problem in the
> > save(stop)/restore(resume) mechanism.
> 
> I should have said "... but six are restored..." instead of "... but four
> are restored..." I also made a small error in a debug string, but it doesn't
> change the read value. If you have any question on my patch, let me know.

That issue is fixed in attachment 69573 [details] [review] which is already upstream.