[PATCH v4 4/8] drm: Add driver-private objects to atomic state

[Maarten Lankhorst]

Op 16-03-17 om 08:10 schreef Dhinakaran Pandiyan:
> From: "Pandiyan, Dhinakaran" <dhinakaran.pandiyan at intel.com>
>
> It is necessary to track states for objects other than connector, crtc
> and plane for atomic modesets. But adding objects like DP MST link
> bandwidth to drm_atomic_state would mean that a non-core object will be
> modified by the core helper functions for swapping and clearing
> it's state. So, lets add void * objects and helper functions that operate
> on void * types to keep these objects and states private to the core.
> Drivers can then implement specific functions to swap and clear states.
> The other advantage having just void * for these objects in
> drm_atomic_state is that objects of different types can be managed in the
> same state array.
>
> v2: Added docs and new iterator to filter private objects (Daniel)
> v3: Macro alignment (Chris)
>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Archit Taneja <architt at codeaurora.org>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Harry Wentland <Harry.wentland at amd.com>
> Acked-by: Harry Wentland <harry.wentland at amd.com>
> Suggested-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>

Mostly looks good, but too many null checks. I think it's best to get rid of them all
by freeing state->driver_private in default_clear() or setting num_private_objs to 0.
It would remove the need for all null checks I think..

~Maarten