drm_modeset_lock oops in next

[Tony Lindgren]

* Maarten Lankhorst <maarten.lankhorst at linux.intel.com> [170408 01:55]:
> Hey,
> 
> Op 07-04-17 om 17:56 schreef Tony Lindgren:
> > Hi,
> >
> > Looks like current next now oopses at least for omapdrm
> > when starting X. Reverting commit d20afeb3e2f9 ("Merge
> > remote-tracking branch 'drm-misc/for-linux-next'") makes
> > things work again.
> >
> > Any ideas what might be causing the oops below?
> Looks like fallout from the acquire_ctx patches?
> 
> Could you test the below?

Yes thanks Daniel Vetter already posted a similar fix as
"[PATCH] drm: Only take cursor locks when the cursor plane exists".

Regards,

Tony