On Wed, 2 Feb 2022 at 11:46, Kandpal Suraj <suraj.kandpal@xxxxxxxxx> wrote:
>
> Changing drm_connector and drm_encoder feilds to pointers in
> drm_writeback_connector as the elements of struct
> drm_writeback_connector are:
> struct drm_writeback_connector {
> struct drm_connector base;
> struct drm_encoder encoder;
> Similarly the elements of intel_encoder and intel_connector
> are:
> struct intel_encoder {
> struct drm_encoder base;
>
> struct intel_connector {
> struct drm_connector base;
>
> The function drm_writeback_connector_init() will initialize the
> drm_connector and drm_encoder and attach them as well.
> Since the drm_connector/encoder are both struct in
> drm_writeback_connector and intel_connector/encoder, we need
> one of them to be a pointer so we can reference them or else we
> will be pointing to 2 seprate instances.
Could you please clarify, why do you want to use intel_connector for
the writeback connector?
I can see a usecase for sharing an encoder between the display and
writback pipelines (and if I'm not mistaken, this is the case for
Abhinav's case).
However, sharing the hardware-backed connector and writeback connector
sounds like a sign of a loose abstraction for me.
Please correct me if I'm wrong and Intel driver would really benefit
from reusing intel_connector as a base for drm_writeback_connector.
> Usually the struct defined in drm framework pointing to any
> struct will be pointer and allocating them and initialization
> will be done with the users.
> Like struct drm_connector and drm_encoder are part of drm
> framework and the users of these such as i915 have included them
> in their struct intel_connector and intel_encoder. Likewise
> struct drm_writeback_connector is a special connector and hence
> is not a user of drm_connector and hence this should be pointers.
>
> Adding drm_writeback_connector to drm_connector so that
> writeback_connector can be fetched from drm_connector as the previous
> container_of method won't work due to change in the feilds of
> drm_connector and drm_encoder in drm_writeback_connector.
>
> Note:The corresponding ripple effect due to the above changes namely in
> two drivers as I can see it komeda and vkms have been dealt with in the
> upcoming patches of this series.
>
> Signed-off-by: Kandpal Suraj <suraj.kandpal@xxxxxxxxx>
>
> Reviewed-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_writeback.c | 19 ++++++++++---------
> include/drm/drm_connector.h | 3 +++
> include/drm/drm_writeback.h | 6 +++---
> 3 files changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
> index dccf4504f1bb..47238db42363 100644
> --- a/drivers/gpu/drm/drm_writeback.c
> +++ b/drivers/gpu/drm/drm_writeback.c
> @@ -87,7 +87,7 @@ static const char *drm_writeback_fence_get_driver_name(struct dma_fence *fence)
> struct drm_writeback_connector *wb_connector =
> fence_to_wb_connector(fence);
>
> - return wb_connector->base.dev->driver->name;
> + return wb_connector->base->dev->driver->name;
> }
>
> static const char *
> @@ -177,7 +177,7 @@ int drm_writeback_connector_init(struct drm_device *dev,
> const u32 *formats, int n_formats)
> {
> struct drm_property_blob *blob;
> - struct drm_connector *connector = &wb_connector->base;
> + struct drm_connector *connector = wb_connector->base;
> struct drm_mode_config *config = &dev->mode_config;
> int ret = create_writeback_properties(dev);
>
> @@ -189,14 +189,15 @@ int drm_writeback_connector_init(struct drm_device *dev,
> if (IS_ERR(blob))
> return PTR_ERR(blob);
>
> - drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs);
> - ret = drm_encoder_init(dev, &wb_connector->encoder,
> + drm_encoder_helper_add(wb_connector->encoder, enc_helper_funcs);
> + ret = drm_encoder_init(dev, wb_connector->encoder,
> &drm_writeback_encoder_funcs,
> DRM_MODE_ENCODER_VIRTUAL, NULL);
> if (ret)
> goto fail;
>
> connector->interlace_allowed = 0;
> + connector->wb_connector = wb_connector;
>
> ret = drm_connector_init(dev, connector, con_funcs,
> DRM_MODE_CONNECTOR_WRITEBACK);
> @@ -204,7 +205,7 @@ int drm_writeback_connector_init(struct drm_device *dev,
> goto connector_fail;
>
> ret = drm_connector_attach_encoder(connector,
> - &wb_connector->encoder);
> + wb_connector->encoder);
> if (ret)
> goto attach_fail;
>
> @@ -233,7 +234,7 @@ int drm_writeback_connector_init(struct drm_device *dev,
> attach_fail:
> drm_connector_cleanup(connector);
> connector_fail:
> - drm_encoder_cleanup(&wb_connector->encoder);
> + drm_encoder_cleanup(wb_connector->encoder);
> fail:
> drm_property_blob_put(blob);
> return ret;
> @@ -263,7 +264,7 @@ int drm_writeback_prepare_job(struct drm_writeback_job *job)
> {
> struct drm_writeback_connector *connector = job->connector;
> const struct drm_connector_helper_funcs *funcs =
> - connector->base.helper_private;
> + connector->base->helper_private;
> int ret;
>
> if (funcs->prepare_writeback_job) {
> @@ -315,7 +316,7 @@ void drm_writeback_cleanup_job(struct drm_writeback_job *job)
> {
> struct drm_writeback_connector *connector = job->connector;
> const struct drm_connector_helper_funcs *funcs =
> - connector->base.helper_private;
> + connector->base->helper_private;
>
> if (job->prepared && funcs->cleanup_writeback_job)
> funcs->cleanup_writeback_job(connector, job);
> @@ -401,7 +402,7 @@ drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector)
> {
> struct dma_fence *fence;
>
> - if (WARN_ON(wb_connector->base.connector_type !=
> + if (WARN_ON(wb_connector->base->connector_type !=
> DRM_MODE_CONNECTOR_WRITEBACK))
> return NULL;
>
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 64cf5f88c05b..fa06faeb7844 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -44,6 +44,7 @@ struct drm_printer;
> struct drm_privacy_screen;
> struct edid;
> struct i2c_adapter;
> +struct drm_writeback_connector;
>
> enum drm_connector_force {
> DRM_FORCE_UNSPECIFIED,
> @@ -1539,6 +1540,8 @@ struct drm_connector {
> */
> struct drm_encoder *encoder;
>
> + struct drm_writeback_connector *wb_connector;
> +
> #define MAX_ELD_BYTES 128
> /** @eld: EDID-like data, if present */
> uint8_t eld[MAX_ELD_BYTES];
> diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
> index 9697d2714d2a..078c9907219c 100644
> --- a/include/drm/drm_writeback.h
> +++ b/include/drm/drm_writeback.h
> @@ -22,7 +22,7 @@ struct drm_writeback_connector {
> /**
> * @base: base drm_connector object
> */
> - struct drm_connector base;
> + struct drm_connector *base;
>
> /**
> * @encoder: Internal encoder used by the connector to fulfill
> @@ -31,7 +31,7 @@ struct drm_writeback_connector {
> * by passing the @enc_funcs parameter to drm_writeback_connector_init()
> * function.
> */
> - struct drm_encoder encoder;
> + struct drm_encoder *encoder;
>
> /**
> * @pixel_formats_blob_ptr:
> @@ -143,7 +143,7 @@ struct drm_writeback_job {
> static inline struct drm_writeback_connector *
> drm_connector_to_writeback(struct drm_connector *connector)
> {
> - return container_of(connector, struct drm_writeback_connector, base);
> + return connector->wb_connector;
> }
>
> int drm_writeback_connector_init(struct drm_device *dev,
> --
> 2.17.1
>
--
With best wishes
Dmitry
