RE: [v3,1/7] drm: writeback: Refactor drm_writeback_connector structure

[Kandpal, Suraj]

> Subject: Re: [v3,1/7] drm: writeback: Refactor drm_writeback_connector
> structure
> 
> On 3/16/26 01:30, 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, this is
> > due to the limitation of inheritance in C.
> > To solve this move the drm_writeback_connector within the
> > drm_connector and remove the drm_connector base which was in
> > drm_writeback_connector. Make this drm_writeback_connector a union
> > with hdmi connector to save memory and since a connector can never be
> > both writeback and hdmi it should serve us well.
> > 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.
> > Modify drivers using the drm_writeback_connector to allow them to use
> > this connector without breaking them.
> > The drivers modified here are amd, komeda, mali, vc4, vkms, rcar_du,
> > msm
> >
> > Signed-off-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> > Reviewed-by: Liviu Dudau <liviu.dudau@xxxxxxx>
> > Reviewed-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>
> > ---
> >   .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  6 +-
> >   .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  2 +-
> >   .../drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c  |  8 +--
> >   .../gpu/drm/arm/display/komeda/komeda_crtc.c  |  6 +-
> >   .../gpu/drm/arm/display/komeda/komeda_kms.h   |  6 +-
> >   .../arm/display/komeda/komeda_wb_connector.c  |  8 +--
> >   drivers/gpu/drm/arm/malidp_crtc.c             |  2 +-
> >   drivers/gpu/drm/arm/malidp_drv.h              |  2 +-
> >   drivers/gpu/drm/arm/malidp_hw.c               |  6 +-
> >   drivers/gpu/drm/arm/malidp_mw.c               |  8 +--
> >   drivers/gpu/drm/drm_atomic_uapi.c             |  2 +-
> >   drivers/gpu/drm/drm_writeback.c               | 35 ++++++----
> >   .../drm/msm/disp/dpu1/dpu_encoder_phys_wb.c   |  3 +-
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c | 16 +++--
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.h |  4 +-
> >   .../gpu/drm/renesas/rcar-du/rcar_du_crtc.h    |  4 +-
> >   .../drm/renesas/rcar-du/rcar_du_writeback.c   | 19 ++---
> >   drivers/gpu/drm/vc4/vc4_txp.c                 | 14 ++--
> >   drivers/gpu/drm/vkms/vkms_composer.c          |  2 +-
> >   drivers/gpu/drm/vkms/vkms_drv.h               |  2 +-
> >   drivers/gpu/drm/vkms/vkms_writeback.c         | 13 ++--
> >   include/drm/drm_connector.h                   | 69 +++++++++++++++++--
> >   include/drm/drm_writeback.h                   | 66 +-----------------
> >   23 files changed, 161 insertions(+), 142 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > index 2f2b1b115bf2..5fe3eb6fc6e1 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > @@ -7219,11 +7219,9 @@ create_stream_for_sink(struct drm_connector
> *connector,
> >   		aconnector = to_amdgpu_dm_connector(connector);
> >   		link = aconnector->dc_link;
> >   	} else {
> > -		struct drm_writeback_connector *wbcon = NULL;
> >   		struct amdgpu_dm_wb_connector *dm_wbcon = NULL;
> >
> > -		wbcon = drm_connector_to_writeback(connector);
> > -		dm_wbcon = to_amdgpu_dm_wb_connector(wbcon);
> > +		dm_wbcon = to_amdgpu_dm_wb_connector(connector);
> >   		link = dm_wbcon->link;
> >   	}
> >
> > @@ -10556,7 +10554,7 @@ static void dm_set_writeback(struct
> amdgpu_display_manager *dm,
> >   			      struct drm_connector *connector,
> >   			      struct drm_connector_state *new_con_state)
> >   {
> > -	struct drm_writeback_connector *wb_conn =
> drm_connector_to_writeback(connector);
> > +	struct drm_writeback_connector *wb_conn = &connector-
> >writeback;
> >   	struct amdgpu_device *adev = dm->adev;
> >   	struct amdgpu_crtc *acrtc;
> >   	struct dc_writeback_info *wb_info;
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> > index 800813671748..705d19f85231 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> > @@ -861,7 +861,7 @@ static inline void
> amdgpu_dm_set_mst_status(uint8_t *status,
> >   #define to_amdgpu_dm_connector(x) container_of(x, struct
> > amdgpu_dm_connector, base)
> >
> >   struct amdgpu_dm_wb_connector {
> > -	struct drm_writeback_connector base;
> > +	struct drm_connector base;
> >   	struct dc_link *link;
> >   };
> >
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c
> > index 80c37487ca77..8fea29720989 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c
> > @@ -202,9 +202,9 @@ int amdgpu_dm_wb_connector_init(struct
> > amdgpu_display_manager *dm,
> >
> >   	wbcon->link = link;
> >
> > -	drm_connector_helper_add(&wbcon->base.base,
> &amdgpu_dm_wb_conn_helper_funcs);
> > +	drm_connector_helper_add(&wbcon->base,
> > +&amdgpu_dm_wb_conn_helper_funcs);
> >
> > -	res = drmm_writeback_connector_init(&dm->adev->ddev, &wbcon-
> >base,
> > +	res = drmm_writeback_connector_init(&dm->adev->ddev,
> > +&wbcon->base.writeback,
> >
> &amdgpu_dm_wb_connector_funcs,
> >   					    encoder,
> >   					    amdgpu_dm_wb_formats,
> > @@ -216,8 +216,8 @@ int amdgpu_dm_wb_connector_init(struct
> amdgpu_display_manager *dm,
> >   	 * Some of the properties below require access to state, like bpc.
> >   	 * Allocate some default initial connector state with our reset helper.
> >   	 */
> > -	if (wbcon->base.base.funcs->reset)
> > -		wbcon->base.base.funcs->reset(&wbcon->base.base);
> > +	if (wbcon->base.funcs->reset)
> > +		wbcon->base.funcs->reset(&wbcon->base);
> >
> >   	return 0;
> >   }
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
> > b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
> > index 9c8b8da531a7..ab7dcc7fd8f3 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
> > @@ -213,7 +213,7 @@ void komeda_crtc_handle_event(struct
> komeda_crtc   *kcrtc,
> >   		struct komeda_wb_connector *wb_conn = kcrtc->wb_conn;
> >
> >   		if (wb_conn)
> > -			drm_writeback_signal_completion(&wb_conn->base,
> 0);
> > +			drm_writeback_signal_completion(&wb_conn-
> >base.writeback, 0);
> >   		else
> >   			drm_warn(drm, "CRTC[%d]: EOW happen but no
> wb_connector.\n",
> >   				 drm_crtc_index(&kcrtc->base));
> > @@ -269,9 +269,9 @@ komeda_crtc_do_flush(struct drm_crtc *crtc,
> >   	if (slave && has_bit(slave->id, kcrtc_st->affected_pipes))
> >   		komeda_pipeline_update(slave, old->state);
> >
> > -	conn_st = wb_conn ? wb_conn->base.base.state : NULL;
> > +	conn_st = wb_conn ? wb_conn->base.state : NULL;
> >   	if (conn_st && conn_st->writeback_job)
> > -		drm_writeback_queue_job(&wb_conn->base, conn_st);
> > +		drm_writeback_queue_job(&wb_conn->base.writeback,
> conn_st);
> >
> >   	/* step 2: notify the HW to kickoff the update */
> >   	mdev->funcs->flush(mdev, master->id, kcrtc_st->active_pipes); diff
> > --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> > b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> > index 83e61c4080c2..9c34302782c0 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> > @@ -53,8 +53,8 @@ struct komeda_plane_state {
> >    * struct komeda_wb_connector
> >    */
> >   struct komeda_wb_connector {
> > -	/** @base: &drm_writeback_connector */
> > -	struct drm_writeback_connector base;
> > +	/** @base: &drm_connector */
> > +	struct drm_connector base;
> >
> >   	/** @wb_layer: represents associated writeback pipeline of komeda
> */
> >   	struct komeda_layer *wb_layer;
> > @@ -139,7 +139,7 @@ struct komeda_kms_dev {
> >   static inline bool is_writeback_only(struct drm_crtc_state *st)
> >   {
> >   	struct komeda_wb_connector *wb_conn = to_kcrtc(st->crtc)-
> >wb_conn;
> > -	struct drm_connector *conn = wb_conn ? &wb_conn->base.base :
> NULL;
> > +	struct drm_connector *conn = wb_conn ? &wb_conn->base : NULL;
> >
> >   	return conn && (st->connector_mask ==
> BIT(drm_connector_index(conn)));
> >   }
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
> > b/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
> > index bcc53d4015f1..fa2f63c142cd 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
> > @@ -53,7 +53,7 @@ komeda_wb_encoder_atomic_check(struct
> drm_encoder *encoder,
> >   		return -EINVAL;
> >   	}
> >
> > -	wb_layer = to_kconn(to_wb_conn(conn_st->connector))->wb_layer;
> > +	wb_layer = to_kconn(conn_st->connector)->wb_layer;
> >
> >   	/*
> >   	 * No need for a full modested when the only connector changed is
> > the @@ -151,7 +151,7 @@ static int komeda_wb_connector_add(struct
> > komeda_kms_dev *kms,
> >
> >   	kwb_conn->wb_layer = kcrtc->master->wb_layer;
> >
> > -	wb_conn = &kwb_conn->base;
> > +	wb_conn = &kwb_conn->base.writeback;
> >
> >   	formats = komeda_get_layer_fourcc_list(&mdev->fmt_tbl,
> >   					       kwb_conn->wb_layer-
> >layer_type, @@ -180,9 +180,9 @@
> > static int komeda_wb_connector_add(struct komeda_kms_dev *kms,
> >   		return err;
> >   	}
> >
> > -	drm_connector_helper_add(&wb_conn->base,
> &komeda_wb_conn_helper_funcs);
> > +	drm_connector_helper_add(&kwb_conn->base,
> > +&komeda_wb_conn_helper_funcs);
> >
> > -	info = &kwb_conn->base.base.display_info;
> > +	info = &kwb_conn->base.display_info;
> >   	info->bpc = __fls(kcrtc->master->improc->supported_color_depths);
> >   	info->color_formats =
> > kcrtc->master->improc->supported_color_formats;
> >
> > diff --git a/drivers/gpu/drm/arm/malidp_crtc.c
> > b/drivers/gpu/drm/arm/malidp_crtc.c
> > index 18e6157b1047..68fa6024be9b 100644
> > --- a/drivers/gpu/drm/arm/malidp_crtc.c
> > +++ b/drivers/gpu/drm/arm/malidp_crtc.c
> > @@ -421,7 +421,7 @@ static int malidp_crtc_atomic_check(struct
> drm_crtc *crtc,
> >   		u32 new_mask = crtc_state->connector_mask;
> >
> >   		if ((old_mask ^ new_mask) ==
> > -		    (1 << drm_connector_index(&malidp-
> >mw_connector.base)))
> > +		    (1 << drm_connector_index(&malidp->mw_connector)))
> >   			crtc_state->connectors_changed = false;
> >   	}
> >
> > diff --git a/drivers/gpu/drm/arm/malidp_drv.h
> > b/drivers/gpu/drm/arm/malidp_drv.h
> > index bc0387876dea..aa5599467d27 100644
> > --- a/drivers/gpu/drm/arm/malidp_drv.h
> > +++ b/drivers/gpu/drm/arm/malidp_drv.h
> > @@ -32,7 +32,7 @@ struct malidp_drm {
> >   	struct drm_device base;
> >   	struct malidp_hw_device *dev;
> >   	struct drm_crtc crtc;
> > -	struct drm_writeback_connector mw_connector;
> > +	struct drm_connector mw_connector;
> >   	wait_queue_head_t wq;
> >   	struct drm_pending_vblank_event *event;
> >   	atomic_t config_valid;
> > diff --git a/drivers/gpu/drm/arm/malidp_hw.c
> > b/drivers/gpu/drm/arm/malidp_hw.c index 9b845d3f34e1..5a7bd27d3718
> > 100644
> > --- a/drivers/gpu/drm/arm/malidp_hw.c
> > +++ b/drivers/gpu/drm/arm/malidp_hw.c
> > @@ -1315,15 +1315,15 @@ static irqreturn_t malidp_se_irq(int irq, void
> *arg)
> >   	if (status & se->vsync_irq) {
> >   		switch (hwdev->mw_state) {
> >   		case MW_ONESHOT:
> > -			drm_writeback_signal_completion(&malidp-
> >mw_connector, 0);
> > +			drm_writeback_signal_completion(&malidp-
> >mw_connector.writeback,
> > +0);
> >   			break;
> >   		case MW_STOP:
> > -			drm_writeback_signal_completion(&malidp-
> >mw_connector, 0);
> > +			drm_writeback_signal_completion(&malidp-
> >mw_connector.writeback,
> > +0);
> >   			/* disable writeback after stop */
> >   			hwdev->mw_state = MW_NOT_ENABLED;
> >   			break;
> >   		case MW_RESTART:
> > -			drm_writeback_signal_completion(&malidp-
> >mw_connector, 0);
> > +			drm_writeback_signal_completion(&malidp-
> >mw_connector.writeback,
> > +0);
> >   			fallthrough;	/* to a new start */
> >   		case MW_START:
> >   			/* writeback started, need to emulate one-shot mode
> */ diff --git
> > a/drivers/gpu/drm/arm/malidp_mw.c
> b/drivers/gpu/drm/arm/malidp_mw.c
> > index 6e0c78e998aa..472598b3e007 100644
> > --- a/drivers/gpu/drm/arm/malidp_mw.c
> > +++ b/drivers/gpu/drm/arm/malidp_mw.c
> > @@ -212,7 +212,7 @@ int malidp_mw_connector_init(struct drm_device
> *drm)
> >   	if (!malidp->dev->hw->enable_memwrite)
> >   		return 0;
> >
> > -	drm_connector_helper_add(&malidp->mw_connector.base,
> > +	drm_connector_helper_add(&malidp->mw_connector,
> >   				 &malidp_mw_connector_helper_funcs);
> >
> >   	formats = get_writeback_formats(malidp, &n_formats); @@ -228,7
> > +228,7 @@ int malidp_mw_connector_init(struct drm_device *drm)
> >
> >   	encoder->possible_crtcs = drm_crtc_mask(&malidp->crtc);
> >
> > -	ret = drmm_writeback_connector_init(drm, &malidp->mw_connector,
> > +	ret = drmm_writeback_connector_init(drm,
> > +&malidp->mw_connector.writeback,
> >   					    &malidp_mw_connector_funcs,
> >   					    encoder,
> >   					    formats, n_formats);
> > @@ -243,8 +243,8 @@ void malidp_mw_atomic_commit(struct
> drm_device *drm,
> >   			     struct drm_atomic_state *old_state)
> >   {
> >   	struct malidp_drm *malidp = drm_to_malidp(drm);
> > -	struct drm_writeback_connector *mw_conn = &malidp-
> >mw_connector;
> > -	struct drm_connector_state *conn_state = mw_conn->base.state;
> > +	struct drm_writeback_connector *mw_conn = &malidp-
> >mw_connector.writeback;
> > +	struct drm_connector_state *conn_state = malidp-
> >mw_connector.state;
> >   	struct malidp_hw_device *hwdev = malidp->dev;
> >   	struct malidp_mw_connector_state *mw_state;
> >
> > diff --git a/drivers/gpu/drm/drm_atomic_uapi.c
> > b/drivers/gpu/drm/drm_atomic_uapi.c
> > index 87de41fb4459..13576a6c25d7 100644
> > --- a/drivers/gpu/drm/drm_atomic_uapi.c
> > +++ b/drivers/gpu/drm/drm_atomic_uapi.c
> > @@ -1468,7 +1468,7 @@ static int prepare_signaling(struct drm_device
> *dev,
> >   		f[*num_fences].out_fence_ptr = fence_ptr;
> >   		*fence_state = f;
> >
> > -		wb_conn = drm_connector_to_writeback(conn);
> > +		wb_conn = &conn->writeback;
> >   		fence = drm_writeback_get_out_fence(wb_conn);
> >   		if (!fence)
> >   			return -ENOMEM;
> > diff --git a/drivers/gpu/drm/drm_writeback.c
> > b/drivers/gpu/drm/drm_writeback.c index 68fdac745f42..7bf9f6374712
> > 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);
> >   	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, @@ -372,7
> > +377,7 @@ int drm_writeback_set_fb(struct drm_connector_state
> *conn_state,
> >   			return -ENOMEM;
> >
> >   		conn_state->writeback_job->connector =
> > -			drm_connector_to_writeback(conn_state-
> >connector);
> > +			&conn_state->connector->writeback;
> >   	}
> >
> >   	drm_framebuffer_assign(&conn_state->writeback_job->fb, fb); @@
> > -381,13 +386,15 @@ int drm_writeback_set_fb(struct
> drm_connector_state
> > *conn_state,
> >
> >   int drm_writeback_prepare_job(struct drm_writeback_job *job)
> >   {
> > -	struct drm_writeback_connector *connector = job->connector;
> > +	struct drm_writeback_connector *wb_connector = job->connector;
> > +	struct drm_connector *connector =
> > +		drm_writeback_to_connector(wb_connector);
> >   	const struct drm_connector_helper_funcs *funcs =
> > -		connector->base.helper_private;
> > +		connector->helper_private;
> >   	int ret;
> >
> >   	if (funcs->prepare_writeback_job) {
> > -		ret = funcs->prepare_writeback_job(connector, job);
> > +		ret = funcs->prepare_writeback_job(wb_connector, job);
> >   		if (ret < 0)
> >   			return ret;
> >   	}
> > @@ -433,12 +440,14 @@ EXPORT_SYMBOL(drm_writeback_queue_job);
> >
> >   void drm_writeback_cleanup_job(struct drm_writeback_job *job)
> >   {
> > -	struct drm_writeback_connector *connector = job->connector;
> > +	struct drm_writeback_connector *wb_connector = job->connector;
> > +	struct drm_connector *connector	=
> > +		drm_writeback_to_connector(wb_connector);
> >   	const struct drm_connector_helper_funcs *funcs =
> > -		connector->base.helper_private;
> > +		connector->helper_private;
> >
> >   	if (job->prepared && funcs->cleanup_writeback_job)
> > -		funcs->cleanup_writeback_job(connector, job);
> > +		funcs->cleanup_writeback_job(wb_connector, job);
> >
> >   	if (job->fb)
> >   		drm_framebuffer_put(job->fb);
> > @@ -520,8 +529,10 @@ struct dma_fence *
> >   drm_writeback_get_out_fence(struct drm_writeback_connector
> *wb_connector)
> >   {
> >   	struct dma_fence *fence;
> > +	struct drm_connector *connector =
> > +		drm_writeback_to_connector(wb_connector);
> >
> > -	if (WARN_ON(wb_connector->base.connector_type !=
> > +	if (WARN_ON(connector->connector_type !=
> >   		    DRM_MODE_CONNECTOR_WRITEBACK))
> >   		return NULL;
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
> > b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
> > index 6d28f2281c76..0375faf7f50c 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
> > @@ -482,7 +482,8 @@ static void
> dpu_encoder_phys_wb_prepare_for_kickoff(
> >   		return;
> >   	}
> >
> > -	drm_conn = &wb_enc->wb_conn->base;
> > +	drm_conn =
> > +		container_of(wb_enc->wb_conn, struct drm_connector,
> writeback);
> Why not 'drm_conn = drm_writeback_to_connector(wb_enc->wb_conn);'?

Right sure will fix this.

> 
> >   	state = drm_conn->state;
> >
> >   	if (wb_enc->wb_conn && wb_enc->wb_job) diff --git
> > a/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
> > b/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
> > index 6f2370c9dd98..930ba1ad777b 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
> > @@ -29,8 +29,7 @@ static int dpu_wb_conn_get_modes(struct
> drm_connector *connector)
> >   static int dpu_wb_conn_atomic_check(struct drm_connector *connector,
> >   				    struct drm_atomic_state *state)
> >   {
> > -	struct drm_writeback_connector *wb_conn =
> drm_connector_to_writeback(connector);
> > -	struct dpu_wb_connector *dpu_wb_conn =
> to_dpu_wb_conn(wb_conn);
> > +	struct dpu_wb_connector *dpu_wb_conn =
> to_dpu_wb_conn(connector);
> >   	struct drm_connector_state *conn_state =
> >   		drm_atomic_get_new_connector_state(state, connector);
> >   	struct drm_crtc *crtc;
> > @@ -88,10 +87,11 @@ static const struct drm_connector_funcs
> dpu_wb_conn_funcs = {
> >   	.atomic_destroy_state =
> drm_atomic_helper_connector_destroy_state,
> >   };
> >
> > -static int dpu_wb_conn_prepare_job(struct drm_writeback_connector
> > *connector,
> > +static int dpu_wb_conn_prepare_job(struct drm_writeback_connector
> > +*wb_conn,
> >   		struct drm_writeback_job *job)
> >   {
> > -
> > +	struct drm_connector *connector =
> > +		container_of(wb_conn, struct drm_connector, writeback);
> As above.

Sure will use the helper here too

> 
> >   	struct dpu_wb_connector *dpu_wb_conn =
> to_dpu_wb_conn(connector);
> >
> >   	if (!job->fb)
> > @@ -102,9 +102,11 @@ static int dpu_wb_conn_prepare_job(struct
> drm_writeback_connector *connector,
> >   	return 0;
> >   }
> >
> > -static void dpu_wb_conn_cleanup_job(struct drm_writeback_connector
> > *connector,
> > +static void dpu_wb_conn_cleanup_job(struct drm_writeback_connector
> > +*wb_connector,
> >   		struct drm_writeback_job *job)
> >   {
> > +	struct drm_connector *connector =
> > +		container_of(wb_connector, struct drm_connector,
> writeback);
> And again.

Sure

> 
> >   	struct dpu_wb_connector *dpu_wb_conn =
> to_dpu_wb_conn(connector);
> >
> >   	if (!job->fb)
> > @@ -132,9 +134,9 @@ int dpu_writeback_init(struct drm_device *dev,
> > struct drm_encoder *enc,
> >
> >   	dpu_wb_conn->maxlinewidth = maxlinewidth;
> >
> > -	drm_connector_helper_add(&dpu_wb_conn->base.base,
> &dpu_wb_conn_helper_funcs);
> > +	drm_connector_helper_add(&dpu_wb_conn->base,
> > +&dpu_wb_conn_helper_funcs);
> >
> > -	rc = drmm_writeback_connector_init(dev, &dpu_wb_conn->base,
> > +	rc = drmm_writeback_connector_init(dev,
> > +&dpu_wb_conn->base.writeback,
> >   					   &dpu_wb_conn_funcs, enc,
> >   					   format_list, num_formats);
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.h
> > b/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.h
> > index 4b11cca8014c..9ebf15392b20 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.h
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.h
> > @@ -16,12 +16,12 @@
> >   #include "dpu_encoder_phys.h"
> >
> >   struct dpu_wb_connector {
> > -	struct drm_writeback_connector base;
> > +	struct drm_connector base;
> >   	struct drm_encoder *wb_enc;
> >   	u32 maxlinewidth;
> >   };
> >
> > -static inline struct dpu_wb_connector *to_dpu_wb_conn(struct
> > drm_writeback_connector *conn)
> > +static inline struct dpu_wb_connector *to_dpu_wb_conn(struct
> > +drm_connector *conn)
> >   {
> >   	return container_of(conn, struct dpu_wb_connector, base);
> >   }
> > diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_crtc.h
> > b/drivers/gpu/drm/renesas/rcar-du/rcar_du_crtc.h
> > index d0f38a8b3561..11937e70e308 100644
> > --- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_crtc.h
> > +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_crtc.h
> > @@ -42,7 +42,7 @@ struct rcar_du_vsp;
> >    * @cmm: CMM associated with this CRTC
> >    * @vsp: VSP feeding video to this CRTC
> >    * @vsp_pipe: index of the VSP pipeline feeding video to this CRTC
> > - * @writeback: the writeback connector
> > + * @writeback: the drm connector which contains the writeback
> > + connector
> >    */
> >   struct rcar_du_crtc {
> >   	struct drm_crtc crtc;
> > @@ -72,7 +72,7 @@ struct rcar_du_crtc {
> >   	const char *const *sources;
> >   	unsigned int sources_count;
> >
> > -	struct drm_writeback_connector writeback;
> > +	struct drm_connector writeback;
> Maybe rename this wb_connector to avoid things like 'rcrtc-
> >writeback.writeback'?
> 
> >   };
> >
> >   #define to_rcar_crtc(c)		container_of(c, struct rcar_du_crtc,
> crtc)
> > diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_writeback.c
> > b/drivers/gpu/drm/renesas/rcar-du/rcar_du_writeback.c
> > index aa37cf99754c..cd09e0fbb030 100644
> > --- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_writeback.c
> > +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_writeback.c
> > @@ -50,7 +50,9 @@ static int rcar_du_wb_conn_get_modes(struct
> drm_connector *connector)
> >   static int rcar_du_wb_prepare_job(struct drm_writeback_connector
> *connector,
> >   				  struct drm_writeback_job *job)
> >   {
> > -	struct rcar_du_crtc *rcrtc = wb_to_rcar_crtc(connector);
> > +	struct drm_connector *conn =
> > +		drm_writeback_to_connector(connector);
> Why line wrap this? It is less than 80 characters as a single line.

Will get it in the same line

> 
> > +	struct rcar_du_crtc *rcrtc = wb_to_rcar_crtc(conn);
> >   	struct rcar_du_wb_job *rjob;
> >   	int ret;
> >
> > @@ -75,7 +77,9 @@ static int rcar_du_wb_prepare_job(struct
> drm_writeback_connector *connector,
> >   static void rcar_du_wb_cleanup_job(struct drm_writeback_connector
> *connector,
> >   				   struct drm_writeback_job *job)
> >   {
> > -	struct rcar_du_crtc *rcrtc = wb_to_rcar_crtc(connector);
> > +	struct drm_connector *conn =
> > +		drm_writeback_to_connector(connector);
> As above.
> 

Sure will fix 

Regards,
Suraj Kandpal

> John.
> 
> > +	struct rcar_du_crtc *rcrtc = wb_to_rcar_crtc(conn);
> >   	struct rcar_du_wb_job *rjob = job->priv;
> >
> >   	if (!job->fb)
> > @@ -199,8 +203,7 @@ static const u32 writeback_formats[] = {
> >   int rcar_du_writeback_init(struct rcar_du_device *rcdu,
> >   			   struct rcar_du_crtc *rcrtc)
> >   {
> > -	struct drm_writeback_connector *wb_conn = &rcrtc->writeback;
> > -
> > +	struct drm_writeback_connector *wb_conn =
> > +&rcrtc->writeback.writeback;
> >   	struct drm_encoder *encoder;
> >
> >   	encoder = drmm_plain_encoder_alloc(&rcdu->ddev, NULL, @@ -
> 212,7
> > +215,7 @@ int rcar_du_writeback_init(struct rcar_du_device *rcdu,
> >
> >   	encoder->possible_crtcs = drm_crtc_mask(&rcrtc->crtc);
> >
> > -	drm_connector_helper_add(&wb_conn->base,
> > +	drm_connector_helper_add(&rcrtc->writeback,
> >   				 &rcar_du_wb_conn_helper_funcs);
> >
> >   	return drmm_writeback_connector_init(&rcdu->ddev, wb_conn, @@
> > -231,7 +234,7 @@ void rcar_du_writeback_setup(struct rcar_du_crtc
> *rcrtc,
> >   	struct drm_framebuffer *fb;
> >   	unsigned int i;
> >
> > -	state = rcrtc->writeback.base.state;
> > +	state = rcrtc->writeback.state;
> >   	if (!state || !state->writeback_job)
> >   		return;
> >
> > @@ -246,10 +249,10 @@ void rcar_du_writeback_setup(struct
> rcar_du_crtc *rcrtc,
> >   		cfg->mem[i] = sg_dma_address(rjob->sg_tables[i].sgl)
> >   			    + fb->offsets[i];
> >
> > -	drm_writeback_queue_job(&rcrtc->writeback, state);
> > +	drm_writeback_queue_job(&rcrtc->writeback.writeback, state);
> >   }
> >
> >   void rcar_du_writeback_complete(struct rcar_du_crtc *rcrtc)
> >   {
> > -	drm_writeback_signal_completion(&rcrtc->writeback, 0);
> > +	drm_writeback_signal_completion(&rcrtc->writeback.writeback, 0);
> >   }
> > diff --git a/drivers/gpu/drm/vc4/vc4_txp.c
> > b/drivers/gpu/drm/vc4/vc4_txp.c index befdb094c173..de3db0834011
> > 100644
> > --- a/drivers/gpu/drm/vc4/vc4_txp.c
> > +++ b/drivers/gpu/drm/vc4/vc4_txp.c
> > @@ -168,7 +168,7 @@ struct vc4_txp {
> >   	struct platform_device *pdev;
> >
> >   	struct vc4_encoder encoder;
> > -	struct drm_writeback_connector connector;
> > +	struct drm_connector connector;
> >
> >   	void __iomem *regs;
> >   };
> > @@ -177,7 +177,7 @@ struct vc4_txp {
> >   	container_of_const(_encoder, struct vc4_txp, encoder.base)
> >
> >   #define connector_to_vc4_txp(_connector)				\
> > -	container_of_const(_connector, struct vc4_txp, connector.base)
> > +	container_of_const(_connector, struct vc4_txp, connector)
> >
> >   static const struct debugfs_reg32 txp_regs[] = {
> >   	VC4_REG32(TXP_DST_PTR),
> > @@ -357,7 +357,7 @@ static void
> vc4_txp_connector_atomic_commit(struct
> > drm_connector *conn,
> >
> >   	TXP_WRITE(TXP_DST_CTRL, ctrl);
> >
> > -	drm_writeback_queue_job(&txp->connector, conn_state);
> > +	drm_writeback_queue_job(&txp->connector.writeback, conn_state);
> >
> >   	drm_dev_exit(idx);
> >   }
> > @@ -505,7 +505,7 @@ static irqreturn_t vc4_txp_interrupt(int irq, void
> *data)
> >   	 */
> >   	TXP_WRITE(TXP_DST_CTRL, TXP_READ(TXP_DST_CTRL) & ~TXP_EI);
> >   	vc4_crtc_handle_vblank(vc4_crtc);
> > -	drm_writeback_signal_completion(&txp->connector, 0);
> > +	drm_writeback_signal_completion(&txp->connector.writeback, 0);
> >
> >   	return IRQ_HANDLED;
> >   }
> > @@ -599,9 +599,9 @@ static int vc4_txp_bind(struct device *dev, struct
> device *master, void *data)
> >   	if (ret)
> >   		return ret;
> >
> > -	drm_connector_helper_add(&txp->connector.base,
> > +	drm_connector_helper_add(&txp->connector,
> >   				 &vc4_txp_connector_helper_funcs);
> > -	ret = drmm_writeback_connector_init(drm, &txp->connector,
> > +	ret = drmm_writeback_connector_init(drm, &txp-
> >connector.writeback,
> >   					    &vc4_txp_connector_funcs,
> >   					    encoder,
> >   					    drm_fmts, ARRAY_SIZE(drm_fmts));
> @@ -623,7 +623,7 @@ static
> > void vc4_txp_unbind(struct device *dev, struct device *master,
> >   {
> >   	struct vc4_txp *txp = dev_get_drvdata(dev);
> >
> > -	drm_connector_cleanup(&txp->connector.base);
> > +	drm_connector_cleanup(&txp->connector);
> >   }
> >
> >   static const struct component_ops vc4_txp_ops = { diff --git
> > a/drivers/gpu/drm/vkms/vkms_composer.c
> > b/drivers/gpu/drm/vkms/vkms_composer.c
> > index cd85de4ffd03..d15623be85fa 100644
> > --- a/drivers/gpu/drm/vkms/vkms_composer.c
> > +++ b/drivers/gpu/drm/vkms/vkms_composer.c
> > @@ -646,7 +646,7 @@ void vkms_composer_worker(struct work_struct
> *work)
> >   		return;
> >
> >   	if (wb_pending) {
> > -		drm_writeback_signal_completion(&out->wb_connector, 0);
> > +		drm_writeback_signal_completion(&out-
> >wb_connector.writeback, 0);
> >   		spin_lock_irq(&out->composer_lock);
> >   		crtc_state->wb_pending = false;
> >   		spin_unlock_irq(&out->composer_lock);
> > diff --git a/drivers/gpu/drm/vkms/vkms_drv.h
> > b/drivers/gpu/drm/vkms/vkms_drv.h index 0933e4ce0ff0..145a7909388b
> > 100644
> > --- a/drivers/gpu/drm/vkms/vkms_drv.h
> > +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> > @@ -217,7 +217,7 @@ struct vkms_crtc_state {
> >    */
> >   struct vkms_output {
> >   	struct drm_crtc crtc;
> > -	struct drm_writeback_connector wb_connector;
> > +	struct drm_connector wb_connector;
> >   	struct drm_encoder wb_encoder;
> >   	struct workqueue_struct *composer_workq;
> >   	spinlock_t lock;
> > diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c
> > b/drivers/gpu/drm/vkms/vkms_writeback.c
> > index 908b7e602ffb..cadb4cb372c5 100644
> > --- a/drivers/gpu/drm/vkms/vkms_writeback.c
> > +++ b/drivers/gpu/drm/vkms/vkms_writeback.c
> > @@ -103,10 +103,13 @@ static int vkms_wb_prepare_job(struct
> drm_writeback_connector *wb_connector,
> >   	return ret;
> >   }
> >
> > -static void vkms_wb_cleanup_job(struct drm_writeback_connector
> > *connector,
> > +static void vkms_wb_cleanup_job(struct drm_writeback_connector
> > +*wb_conn,
> >   				struct drm_writeback_job *job)
> >   {
> >   	struct vkms_writeback_job *vkmsjob = job->priv;
> > +	struct drm_connector *connector = container_of(wb_conn,
> > +						       struct drm_connector,
> > +						       writeback);
> >   	struct vkms_output *vkms_output = container_of(connector,
> >   						       struct vkms_output,
> >   						       wb_connector);
> > @@ -128,8 +131,8 @@ static void vkms_wb_atomic_commit(struct
> drm_connector *conn,
> >   	struct drm_connector_state *connector_state =
> drm_atomic_get_new_connector_state(state,
> >
> 		 conn);
> >   	struct vkms_output *output =
> drm_crtc_to_vkms_output(connector_state->crtc);
> > -	struct drm_writeback_connector *wb_conn = &output-
> >wb_connector;
> > -	struct drm_connector_state *conn_state = wb_conn->base.state;
> > +	struct drm_writeback_connector *wb_conn = &output-
> >wb_connector.writeback;
> > +	struct drm_connector_state *conn_state = output-
> >wb_connector.state;
> >   	struct vkms_crtc_state *crtc_state = output->composer_state;
> >   	struct drm_framebuffer *fb = connector_state->writeback_job->fb;
> >   	u16 crtc_height = crtc_state->base.mode.vdisplay; @@ -167,7 +170,7
> > @@ static const struct drm_connector_helper_funcs
> vkms_wb_conn_helper_funcs = {
> >   int vkms_enable_writeback_connector(struct vkms_device *vkmsdev,
> >   				    struct vkms_output *vkms_output)
> >   {
> > -	struct drm_writeback_connector *wb = &vkms_output-
> >wb_connector;
> > +	struct drm_writeback_connector *wb =
> > +&vkms_output->wb_connector.writeback;
> >   	int ret;
> >
> >   	ret = drmm_encoder_init(&vkmsdev->drm, &vkms_output-
> >wb_encoder, @@
> > -178,7 +181,7 @@ int vkms_enable_writeback_connector(struct
> vkms_device *vkmsdev,
> >   	vkms_output->wb_encoder.possible_clones |=
> >   		drm_encoder_mask(&vkms_output->wb_encoder);
> >
> > -	drm_connector_helper_add(&wb->base,
> &vkms_wb_conn_helper_funcs);
> > +	drm_connector_helper_add(&vkms_output->wb_connector,
> > +&vkms_wb_conn_helper_funcs);
> >
> >   	return drmm_writeback_connector_init(&vkmsdev->drm, wb,
> >   					     &vkms_wb_connector_funcs,
> > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> > index c18be8c19de0..7032bb42d06f 100644
> > --- a/include/drm/drm_connector.h
> > +++ b/include/drm/drm_connector.h
> > @@ -1927,6 +1927,61 @@ struct drm_connector_cec {
> >   	void *data;
> >   };
> >
> > +/**
> > + * struct drm_writeback_connector - DRM writeback connector  */
> > +struct drm_writeback_connector {
> > +	/**
> > +	 * @pixel_formats_blob_ptr:
> > +	 *
> > +	 * DRM blob property data for the pixel formats list on writeback
> > +	 * connectors
> > +	 * See also drm_writeback_connector_init()
> > +	 */
> > +	struct drm_property_blob *pixel_formats_blob_ptr;
> > +
> > +	/** @job_lock: Protects job_queue */
> > +	spinlock_t job_lock;
> > +
> > +	/**
> > +	 * @job_queue:
> > +	 *
> > +	 * Holds a list of a connector's writeback jobs; the last item is the
> > +	 * most recent. The first item may be either waiting for the hardware
> > +	 * to begin writing, or currently being written.
> > +	 *
> > +	 * See also: drm_writeback_queue_job() and
> > +	 * drm_writeback_signal_completion()
> > +	 */
> > +	struct list_head job_queue;
> > +
> > +	/**
> > +	 * @fence_context:
> > +	 *
> > +	 * timeline context used for fence operations.
> > +	 */
> > +	unsigned int fence_context;
> > +	/**
> > +	 * @fence_lock:
> > +	 *
> > +	 * spinlock to protect the fences in the fence_context.
> > +	 */
> > +	spinlock_t fence_lock;
> > +	/**
> > +	 * @fence_seqno:
> > +	 *
> > +	 * Seqno variable used as monotonic counter for the fences
> > +	 * created on the connector's timeline.
> > +	 */
> > +	unsigned long fence_seqno;
> > +	/**
> > +	 * @timeline_name:
> > +	 *
> > +	 * The name of the connector's fence timeline.
> > +	 */
> > +	char timeline_name[32];
> > +};
> > +
> >   /**
> >    * struct drm_connector - central DRM connector control structure
> >    *
> > @@ -2336,10 +2391,16 @@ struct drm_connector {
> >   	 */
> >   	struct llist_node free_node;
> >
> > -	/**
> > -	 * @hdmi: HDMI-related variable and properties.
> > -	 */
> > -	struct drm_connector_hdmi hdmi;
> > +	union {
> > +		/**
> > +		 * @hdmi: HDMI-related variable and properties.
> > +		 */
> > +		struct drm_connector_hdmi hdmi;
> > +		/**
> > +		 * @writeback: Writeback related valriables.
> > +		 */
> > +		struct drm_writeback_connector writeback;
> > +	};
> >
> >   	/**
> >   	 * @hdmi_audio: HDMI codec properties and non-DRM state.
> > diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
> > index 958466a05e60..702141099520 100644
> > --- a/include/drm/drm_writeback.h
> > +++ b/include/drm/drm_writeback.h
> > @@ -15,66 +15,6 @@
> >   #include <drm/drm_encoder.h>
> >   #include <linux/workqueue.h>
> >
> > -/**
> > - * struct drm_writeback_connector - DRM writeback connector
> > - */
> > -struct drm_writeback_connector {
> > -	/**
> > -	 * @base: base drm_connector object
> > -	 */
> > -	struct drm_connector base;
> > -
> > -	/**
> > -	 * @pixel_formats_blob_ptr:
> > -	 *
> > -	 * DRM blob property data for the pixel formats list on writeback
> > -	 * connectors
> > -	 * See also drm_writeback_connector_init()
> > -	 */
> > -	struct drm_property_blob *pixel_formats_blob_ptr;
> > -
> > -	/** @job_lock: Protects job_queue */
> > -	spinlock_t job_lock;
> > -
> > -	/**
> > -	 * @job_queue:
> > -	 *
> > -	 * Holds a list of a connector's writeback jobs; the last item is the
> > -	 * most recent. The first item may be either waiting for the hardware
> > -	 * to begin writing, or currently being written.
> > -	 *
> > -	 * See also: drm_writeback_queue_job() and
> > -	 * drm_writeback_signal_completion()
> > -	 */
> > -	struct list_head job_queue;
> > -
> > -	/**
> > -	 * @fence_context:
> > -	 *
> > -	 * timeline context used for fence operations.
> > -	 */
> > -	unsigned int fence_context;
> > -	/**
> > -	 * @fence_lock:
> > -	 *
> > -	 * spinlock to protect the fences in the fence_context.
> > -	 */
> > -	spinlock_t fence_lock;
> > -	/**
> > -	 * @fence_seqno:
> > -	 *
> > -	 * Seqno variable used as monotonic counter for the fences
> > -	 * created on the connector's timeline.
> > -	 */
> > -	unsigned long fence_seqno;
> > -	/**
> > -	 * @timeline_name:
> > -	 *
> > -	 * The name of the connector's fence timeline.
> > -	 */
> > -	char timeline_name[32];
> > -};
> > -
> >   /**
> >    * struct drm_writeback_job - DRM writeback job
> >    */
> > @@ -131,10 +71,10 @@ struct drm_writeback_job {
> >   	void *priv;
> >   };
> >
> > -static inline struct drm_writeback_connector *
> > -drm_connector_to_writeback(struct drm_connector *connector)
> > +static inline struct drm_connector *
> > +drm_writeback_to_connector(struct drm_writeback_connector
> > +*wb_connector)
> >   {
> > -	return container_of(connector, struct drm_writeback_connector,
> base);
> > +	return container_of(wb_connector, struct drm_connector, writeback);
> >   }
> >
> >   int drm_writeback_connector_init(struct drm_device *dev,