[PATCH] drm/bochs: Fix NULL dereference on atomic_disable helper

[Gerd Hoffmann]

  Hi,

> > >  static void bochs_crtc_atomic_flush(struct drm_crtc *crtc,
> > >  				    struct drm_crtc_state *old_crtc_state)
> > >  {
> > > @@ -66,6 +71,7 @@ static const struct drm_crtc_funcs bochs_crtc_funcs = {
> > >  static const struct drm_crtc_helper_funcs bochs_helper_funcs = {
> > >  	.mode_set_nofb = bochs_crtc_mode_set_nofb,
> > >  	.atomic_enable = bochs_crtc_atomic_enable,
> > > +	.atomic_disable = bochs_crtc_atomic_disable,
> > 
> > Shouldn't we make the callback optional instead of adding empty dummy
> > functions to drivers?
> 
> Hi Gerd,
> 
> I agree, and I can work in this issue.
> Just one question, should we make atomic_enable optional as well?

IIRC the drm code checks for the atomic_enable callback presence to
figure whenever it should take the atomic or legacy code paths.

So, I think that will not work.

cheers,
  Gerd