[PATCH V3] drm_crtc: check if fb_create return NULL

[Su, Xuemin]

On Thu, 2013-01-24 at 10:31 +0200, Jani Nikula wrote:
> >  	}
> > +	/* some buggy driver may return NULL here, which may cause panic */
> > +	BUG_ON(!fb);
> 
> I fail to see the benefit of this compared to just letting it oops...
> 
> >  	or->fb_id = fb->base.id;
> 
> ...right here.
> 
> 
For PATCH V3, I think a BUG_ON may give the user clearer information
about the reason of panic. Easier to debug.
I submitted a PATCH V2 yesterday which gives a warning and then return
-EVAL if fb==NULL, preventing the panic. Do you think this is
acceptable?