[RFC PATCH 1/8] drm: writeback: Refactor drm_writeback_connector structure

[Dmitry Baryshkov]

On Mon, Aug 11, 2025 at 02:57:00PM +0530, Suraj Kandpal wrote:
> Some drivers cannot work with the current design where the connector
> is embedded within the drm_writeback_connector such as intel and
> some drivers that can get it working end up adding a lot of checks
> all around the code to check if it's a writeback conenctor or not.
> To solve this we move the drm_writeback_connector within the
> drm_connector and remove the drm_connector base which was in
> drm_writeback_connector. We do all other required
> modifications that come with these changes along with addition
> of new function which returns the drm_connector when
> drm_writeback_connector is present.
> All drivers will be expected to allocate the drm_connector.
> 
> Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> ---
>  drivers/gpu/drm/drm_writeback.c | 33 ++++++++++------
>  include/drm/drm_connector.h     | 60 +++++++++++++++++++++++++++++
>  include/drm/drm_writeback.h     | 68 ++++-----------------------------
>  3 files changed, 89 insertions(+), 72 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
> index ec2575c4c21b..198b8c488056 100644
> --- a/drivers/gpu/drm/drm_writeback.c
> +++ b/drivers/gpu/drm/drm_writeback.c
> @@ -89,8 +89,10 @@ static const char *drm_writeback_fence_get_driver_name(struct dma_fence *fence)
>  {
>  	struct drm_writeback_connector *wb_connector =
>  		fence_to_wb_connector(fence);
> +	struct drm_connector *connector =
> +		drm_writeback_to_connector(wb_connector);
>  
> -	return wb_connector->base.dev->driver->name;
> +	return connector->dev->driver->name;
>  }
>  
>  static const char *
> @@ -187,7 +189,8 @@ static int __drm_writeback_connector_init(struct drm_device *dev,
>  					  struct drm_encoder *enc, const u32 *formats,
>  					  int n_formats)
>  {
> -	struct drm_connector *connector = &wb_connector->base;
> +	struct drm_connector *connector =
> +		drm_writeback_to_connector(wb_connector);
>  	struct drm_mode_config *config = &dev->mode_config;
>  	struct drm_property_blob *blob;
>  	int ret = create_writeback_properties(dev);
> @@ -269,7 +272,8 @@ int drm_writeback_connector_init(struct drm_device *dev,
>  				 struct drm_encoder *enc,
>  				 const u32 *formats, int n_formats)
>  {
> -	struct drm_connector *connector = &wb_connector->base;
> +	struct drm_connector *connector =
> +		drm_writeback_to_connector(wb_connector);

Please pass drm_connector instead (to all init functions). It would make
more sense.

>  	int ret;
>  
>  	ret = drm_connector_init(dev, connector, con_funcs,
> @@ -339,7 +343,8 @@ int drmm_writeback_connector_init(struct drm_device *dev,
>  				  struct drm_encoder *enc,
>  				  const u32 *formats, int n_formats)
>  {
> -	struct drm_connector *connector = &wb_connector->base;
> +	struct drm_connector *connector =
> +		drm_writeback_to_connector(wb_connector);
>  	int ret;
>  
>  	ret = drmm_connector_init(dev, connector, con_funcs,

-- 
With best wishes
Dmitry