Re: [PATCH v2 01/28] drm/atomic: Fix unused but set warning in state iterator macros

[Simona Vetter]

On Thu, Apr 23, 2026 at 12:18:14PM +0200, Maxime Ripard wrote:
> A number of state iterator macros trigger a compiler warning if an
> iterator parameter isn't used in the code block.
> 
> Add a similar workaround than in most other macros.

I'm not on top of macro-fu, so not leaning out the window and dropping an
r-b here. But sounds reasonable.

Acked-by: Simona Vetter <simona.vetter@xxxxxxxx>

> 
> Signed-off-by: Maxime Ripard <mripard@xxxxxxxxxx>
> ---
>  include/drm/drm_atomic.h | 64 +++++++++++++++++++++++++++++++-----------------
>  1 file changed, 42 insertions(+), 22 deletions(-)
> 
> diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
> index f03cd199aee7..b9e7281cfc97 100644
> --- a/include/drm/drm_atomic.h
> +++ b/include/drm/drm_atomic.h
> @@ -946,13 +946,15 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>  	for ((__i) = 0;								\
>  	     (__i) < (__state)->num_connector;					\
>  	     (__i)++)								\
>  		for_each_if ((__state)->connectors[__i].ptr &&			\
>  			     ((connector) = (__state)->connectors[__i].ptr,	\
> -			     (void)(connector) /* Only to avoid unused-but-set-variable warning */, \
> -			     (old_connector_state) = (__state)->connectors[__i].old_state,	\
> -			     (new_connector_state) = (__state)->connectors[__i].new_state, 1))
> +			      (void)(connector) /* Only to avoid unused-but-set-variable warning */, \
> +			      (old_connector_state) = (__state)->connectors[__i].old_state,	\
> +			      (void)(old_connector_state) /* Only to avoid unused-but-set-variable warning */, \
> +			      (new_connector_state) = (__state)->connectors[__i].new_state,	\
> +			      (void)(new_connector_state) /* Only to avoid unused-but-set-variable warning */, 1))
>  
>  /**
>   * for_each_old_connector_in_state - iterate over all connectors in an atomic update
>   * @__state: &struct drm_atomic_state pointer
>   * @connector: &struct drm_connector iteration cursor
> @@ -968,12 +970,13 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>  	for ((__i) = 0;								\
>  	     (__i) < (__state)->num_connector;					\
>  	     (__i)++)								\
>  		for_each_if ((__state)->connectors[__i].ptr &&			\
>  			     ((connector) = (__state)->connectors[__i].ptr,	\
> -			     (void)(connector) /* Only to avoid unused-but-set-variable warning */, \
> -			     (old_connector_state) = (__state)->connectors[__i].old_state, 1))
> +			      (void)(connector) /* Only to avoid unused-but-set-variable warning */, \
> +			      (old_connector_state) = (__state)->connectors[__i].old_state, \
> +			      (void)(old_connector_state) /* Only to avoid unused-but-set-variable warning */, 1))
>  
>  /**
>   * for_each_new_connector_in_state - iterate over all connectors in an atomic update
>   * @__state: &struct drm_atomic_state pointer
>   * @connector: &struct drm_connector iteration cursor
> @@ -989,13 +992,13 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>  	for ((__i) = 0;								\
>  	     (__i) < (__state)->num_connector;					\
>  	     (__i)++)								\
>  		for_each_if ((__state)->connectors[__i].ptr &&			\
>  			     ((connector) = (__state)->connectors[__i].ptr,	\
> -			     (void)(connector) /* Only to avoid unused-but-set-variable warning */, \
> -			     (new_connector_state) = (__state)->connectors[__i].new_state, \
> -			     (void)(new_connector_state) /* Only to avoid unused-but-set-variable warning */, 1))
> +			      (void)(connector) /* Only to avoid unused-but-set-variable warning */, \
> +			      (new_connector_state) = (__state)->connectors[__i].new_state, \
> +			      (void)(new_connector_state) /* Only to avoid unused-but-set-variable warning */, 1))
>  
>  /**
>   * for_each_oldnew_crtc_in_state - iterate over all CRTCs in an atomic update
>   * @__state: &struct drm_atomic_state pointer
>   * @crtc: &struct drm_crtc iteration cursor
> @@ -1012,14 +1015,14 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>  	     (__i) < (__state)->dev->mode_config.num_crtc;		\
>  	     (__i)++)							\
>  		for_each_if ((__state)->crtcs[__i].ptr &&		\
>  			     ((crtc) = (__state)->crtcs[__i].ptr,	\
>  			      (void)(crtc) /* Only to avoid unused-but-set-variable warning */, \
> -			     (old_crtc_state) = (__state)->crtcs[__i].old_state, \
> -			     (void)(old_crtc_state) /* Only to avoid unused-but-set-variable warning */, \
> -			     (new_crtc_state) = (__state)->crtcs[__i].new_state, \
> -			     (void)(new_crtc_state) /* Only to avoid unused-but-set-variable warning */, 1))
> +			      (old_crtc_state) = (__state)->crtcs[__i].old_state, \
> +			      (void)(old_crtc_state) /* Only to avoid unused-but-set-variable warning */, \
> +			      (new_crtc_state) = (__state)->crtcs[__i].new_state, \
> +			      (void)(new_crtc_state) /* Only to avoid unused-but-set-variable warning */, 1))
>  
>  /**
>   * for_each_old_crtc_in_state - iterate over all CRTCs in an atomic update
>   * @__state: &struct drm_atomic_state pointer
>   * @crtc: &struct drm_crtc iteration cursor
> @@ -1035,11 +1038,12 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>  	     (__i) < (__state)->dev->mode_config.num_crtc;		\
>  	     (__i)++)							\
>  		for_each_if ((__state)->crtcs[__i].ptr &&		\
>  			     ((crtc) = (__state)->crtcs[__i].ptr,	\
>  			     (void)(crtc) /* Only to avoid unused-but-set-variable warning */, \
> -			     (old_crtc_state) = (__state)->crtcs[__i].old_state, 1))
> +			     (old_crtc_state) = (__state)->crtcs[__i].old_state, \
> +			     (void)(old_crtc_state) /* Only to avoid unused-but-set-variable warning */, 1))
>  
>  /**
>   * for_each_new_crtc_in_state - iterate over all CRTCs in an atomic update
>   * @__state: &struct drm_atomic_state pointer
>   * @crtc: &struct drm_crtc iteration cursor
> @@ -1120,12 +1124,14 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>  	     (__i) < (__state)->dev->mode_config.num_total_plane;	\
>  	     (__i)++)							\
>  		for_each_if ((__state)->planes[__i].ptr &&		\
>  			     ((plane) = (__state)->planes[__i].ptr,	\
>  			      (void)(plane) /* Only to avoid unused-but-set-variable warning */, \
> -			      (old_plane_state) = (__state)->planes[__i].old_state,\
> -			      (new_plane_state) = (__state)->planes[__i].new_state, 1))
> +			      (old_plane_state) = (__state)->planes[__i].old_state, \
> +			      (void)(old_plane_state) /* Only to avoid unused-but-set-variable warning */, \
> +			      (new_plane_state) = (__state)->planes[__i].new_state, \
> +			      (void)(new_plane_state) /* Only to avoid unused-but-set-variable warning */, 1))
>  
>  /**
>   * for_each_oldnew_plane_in_state_reverse - iterate over all planes in an atomic
>   * update in reverse order
>   * @__state: &struct drm_atomic_state pointer
> @@ -1142,12 +1148,15 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>  	for ((__i) = ((__state)->dev->mode_config.num_total_plane - 1);	\
>  	     (__i) >= 0;						\
>  	     (__i)--)							\
>  		for_each_if ((__state)->planes[__i].ptr &&		\
>  			     ((plane) = (__state)->planes[__i].ptr,	\
> -			      (old_plane_state) = (__state)->planes[__i].old_state,\
> -			      (new_plane_state) = (__state)->planes[__i].new_state, 1))
> +			      (void)(plane) /* Only to avoid unused-but-set-variable warning */, \
> +			      (old_plane_state) = (__state)->planes[__i].old_state, \
> +			      (void)(old_plane_state) /* Only to avoid unused-but-set-variable warning */, \
> +			      (new_plane_state) = (__state)->planes[__i].new_state, \
> +			      (void)(new_plane_state) /* Only to avoid unused-but-set-variable warning */, 1))
>  
>  /**
>   * for_each_new_plane_in_state_reverse - other than only tracking new state,
>   * it's the same as for_each_oldnew_plane_in_state_reverse
>   * @__state: &struct drm_atomic_state pointer
> @@ -1159,11 +1168,13 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>  	for ((__i) = ((__state)->dev->mode_config.num_total_plane - 1);	\
>  	     (__i) >= 0;						\
>  	     (__i)--)							\
>  		for_each_if ((__state)->planes[__i].ptr &&		\
>  			     ((plane) = (__state)->planes[__i].ptr,	\
> -			      (new_plane_state) = (__state)->planes[__i].new_state, 1))
> +			      (void)(plane) /* Only to avoid unused-but-set-variable warning */, \
> +			      (new_plane_state) = (__state)->planes[__i].new_state, \
> +			      (void)(new_plane_state) /* Only to avoid unused-but-set-variable warning */, 1))
>  
>  /**
>   * for_each_old_plane_in_state - iterate over all planes in an atomic update
>   * @__state: &struct drm_atomic_state pointer
>   * @plane: &struct drm_plane iteration cursor
> @@ -1178,11 +1189,14 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>  	for ((__i) = 0;							\
>  	     (__i) < (__state)->dev->mode_config.num_total_plane;	\
>  	     (__i)++)							\
>  		for_each_if ((__state)->planes[__i].ptr &&		\
>  			     ((plane) = (__state)->planes[__i].ptr,	\
> -			      (old_plane_state) = (__state)->planes[__i].old_state, 1))
> +			      (void)(plane) /* Only to avoid unused-but-set-variable warning */, \
> +			      (old_plane_state) = (__state)->planes[__i].old_state, \
> +			      (void)(old_plane_state) /* Only to avoid unused-but-set-variable warning */, 1))
> +
>  /**
>   * for_each_new_plane_in_state - iterate over all planes in an atomic update
>   * @__state: &struct drm_atomic_state pointer
>   * @plane: &struct drm_plane iteration cursor
>   * @new_plane_state: &struct drm_plane_state iteration cursor for the new state
> @@ -1216,12 +1230,15 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>   */
>  #define for_each_oldnew_private_obj_in_state(__state, obj, old_obj_state, new_obj_state, __i) \
>  	for ((__i) = 0; \
>  	     (__i) < (__state)->num_private_objs && \
>  		     ((obj) = (__state)->private_objs[__i].ptr, \
> +		      (void)(obj) /* Only to avoid unused-but-set-variable warning */, \
>  		      (old_obj_state) = (__state)->private_objs[__i].old_state,	\
> -		      (new_obj_state) = (__state)->private_objs[__i].new_state, 1); \
> +		      (void)(old_obj_state) /* Only to avoid unused-but-set-variable warning */, \
> +		      (new_obj_state) = (__state)->private_objs[__i].new_state, \
> +		      (void)(new_obj_state) /* Only to avoid unused-but-set-variable warning */, 1); \
>  	     (__i)++)
>  
>  /**
>   * for_each_old_private_obj_in_state - iterate over all private objects in an atomic update
>   * @__state: &struct drm_atomic_state pointer
> @@ -1235,11 +1252,13 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>   */
>  #define for_each_old_private_obj_in_state(__state, obj, old_obj_state, __i) \
>  	for ((__i) = 0; \
>  	     (__i) < (__state)->num_private_objs && \
>  		     ((obj) = (__state)->private_objs[__i].ptr, \
> -		      (old_obj_state) = (__state)->private_objs[__i].old_state, 1); \
> +		      (void)(obj) /* Only to avoid unused-but-set-variable warning */, \
> +		      (old_obj_state) = (__state)->private_objs[__i].old_state, \
> +		      (void)(old_obj_state) /* Only to avoid unused-but-set-variable warning */, 1); \
>  	     (__i)++)
>  
>  /**
>   * for_each_new_private_obj_in_state - iterate over all private objects in an atomic update
>   * @__state: &struct drm_atomic_state pointer
> @@ -1254,11 +1273,12 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
>  #define for_each_new_private_obj_in_state(__state, obj, new_obj_state, __i) \
>  	for ((__i) = 0; \
>  	     (__i) < (__state)->num_private_objs && \
>  		     ((obj) = (__state)->private_objs[__i].ptr, \
>  		      (void)(obj) /* Only to avoid unused-but-set-variable warning */, \
> -		      (new_obj_state) = (__state)->private_objs[__i].new_state, 1); \
> +		      (new_obj_state) = (__state)->private_objs[__i].new_state, \
> +		      (void)(new_obj_state) /* Only to avoid unused-but-set-variable warning */, 1); \
>  	     (__i)++)
>  
>  /**
>   * drm_atomic_crtc_needs_modeset - compute combined modeset need
>   * @state: &drm_crtc_state for the CRTC
> 
> -- 
> 2.53.0
> 

-- 
Simona Vetter
Software Engineer
http://blog.ffwll.ch