[Intel-gfx] [PATCH 1/3] drm: add writeback pointers to drm_connector

[Kandpal, Suraj]

Hey,
> I think there are more places affected with this change. I can get below
> compilation issues while trying to compile my branch:
> 
> drivers/gpu/drm/vc4/vc4_txp.c: In function ‘encoder_to_vc4_txp’:
> ./include/linux/build_bug.h:78:41: error: static assertion failed:
> "pointer type mismatch in container_of()"
>   #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
>                                           ^
> ./include/linux/build_bug.h:77:34: note: in expansion of macro
> ‘__static_assert’
>   #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__,
> #expr)
>                                    ^
> ./include/linux/container_of.h:19:2: note: in expansion of macro
> ‘static_assert’
>    static_assert(__same_type(*(ptr), ((type *)0)->member) || \
>    ^
> drivers/gpu/drm/vc4/vc4_txp.c:162:9: note: in expansion of macro
> ‘container_of’
>    return container_of(encoder, struct vc4_txp, connector.encoder);
>           ^
> drivers/gpu/drm/vc4/vc4_txp.c: In function ‘connector_to_vc4_txp’:
> ./include/linux/build_bug.h:78:41: error: static assertion failed:
> "pointer type mismatch in container_of()"
>   #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
>                                           ^
> ./include/linux/build_bug.h:77:34: note: in expansion of macro
> ‘__static_assert’
>   #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__,
> #expr)
>                                    ^
> ./include/linux/container_of.h:19:2: note: in expansion of macro
> ‘static_assert’
>    static_assert(__same_type(*(ptr), ((type *)0)->member) || \
>    ^
> drivers/gpu/drm/vc4/vc4_txp.c:167:9: note: in expansion of macro
> ‘container_of’
>    return container_of(conn, struct vc4_txp, connector.base);
>           ^
> drivers/gpu/drm/vc4/vc4_txp.c: In function ‘vc4_txp_bind’:
> drivers/gpu/drm/vc4/vc4_txp.c:495:27: error: passing argument 1 of
> ‘drm_connector_helper_add’ from incompatible pointer type [-
> Werror=incompatible-pointer-types]
>    drm_connector_helper_add(&txp->connector.base,
>                             ^
> In file included from ./include/drm/drm_atomic_helper.h:32:0,
>                   from drivers/gpu/drm/vc4/vc4_txp.c:17:
> ./include/drm/drm_modeset_helper_vtables.h:1153:20: note: expected
> ‘struct drm_connector *’ but argument is of type ‘struct drm_connector **’
>   static inline void drm_connector_helper_add(struct drm_connector
> *connector,
>                      ^
> drivers/gpu/drm/vc4/vc4_txp.c:509:10: error: assignment from incompatible
> pointer type [-Werror=incompatible-pointer-types]
>    encoder = &txp->connector.encoder;
>            ^
> drivers/gpu/drm/vc4/vc4_txp.c: In function ‘vc4_txp_unbind’:
> drivers/gpu/drm/vc4/vc4_txp.c:532:28: error: passing argument 1 of
> ‘vc4_txp_connector_destroy’ from incompatible pointer type [-
> Werror=incompatible-pointer-types]
>    vc4_txp_connector_destroy(&txp->connector.base);
>                              ^
> drivers/gpu/drm/vc4/vc4_txp.c:333:13: note: expected ‘struct
> drm_connector *’ but argument is of type ‘struct drm_connector **’
>   static void vc4_txp_connector_destroy(struct drm_connector *connector)
> 
I will have a look at this and try to resolve it
> 
> Looks like vc4 doesnt have its own encoder so we might have to move it to
> have its own?

Right seems like we will have to add a drm_connector and drm_encoder in the 
below structure
> 
> struct vc4_txp {
>      struct vc4_crtc base;
> 
>      struct platform_device *pdev;
> 
>      struct drm_writeback_connector connector;
> 
>      void __iomem *regs;
>      struct debugfs_regset32 regset;
> };
> 
> static inline struct vc4_txp *encoder_to_vc4_txp(struct drm_encoder
> *encoder)
> {
>      return container_of(encoder, struct vc4_txp, connector.encoder); }
> 
> static inline struct vc4_txp *connector_to_vc4_txp(struct drm_connector
> *conn)
> {
>      return container_of(conn, struct vc4_txp, connector.base); }
> 

Changes will be required here in both connector_of functions to point to 
The new drm_connector and drm_encoder we add in vc4_txp struct.

> 
> One more thing, it looks like to me, we need to do one more thing.
> 
> Like intel does and what MSM will do, the encoder pointer of the wb
> connector has to point to the encoder struct .
> 
>  >> wb_conn = &intel_connector->wb_conn;
>  >> wb_conn->base = &intel_connector->base;
>  >> wb_conn->encoder = &intel_wd->base.base;
> 
Yes this will need to be done 

Thanks Abhinav for pointing Ill implement this and send it in the next version
of patches 

Regards,
Suraj Kandpal