[PATCH v2 0/6] Allow drm_writeback_connector to accept pointer to drm_encoder

[Dmitry Baryshkov]

Hi Abhinav,

On 16/03/2022 02:11, Abhinav Kumar wrote:
> There are some vendor drivers for which the writeback encoder shares
> hardware resources such as clocks and interrupts with the rest of the
> display pipeline. In addition, there can be use-cases where the
> writeback encoder could be a shared encoder between the physical display
> path and the writeback path.
> 
> To accommodate for such cases, change the drm_writeback_connector to
> accept a pointer to drm_encoder.
> 
> For existing users of drm_writeback_connector there will not be any
> change in functionality due to this change.
> 
> This approach was first posted by Suraj Kandpal here [1] for both
> encoder and connector. But after discussions [2], the consensus was
> reached to split this change for the drm_encoder first and the
> drm_connector part can be reworked in a subsequent change later.
> 
> Validation of this change was done using igt_writeback tests on
> MSM based RB5 board using the changes posted here [3].
> 
> For all other chipsets, these changes were compile-tested.
> 
> [1] https://patchwork.kernel.org/project/dri-devel/patch/20220202081702.22119-1-suraj.kandpal@intel.com/
> [2] https://patchwork.kernel.org/project/dri-devel/patch/20220202085429.22261-6-suraj.kandpal@intel.com/
> [3] https://patchwork.freedesktop.org/series/99724/
> 
> changes in v2:
>      - introduce a new API drm_writeback_connector_init_with_encoder()
>      - allow passing possible_crtcs for existing users of
>        drm_writeback_connector_init()
> 
> Abhinav Kumar (6):
>    drm: allow real encoder to be passed for drm_writeback_connector
>    drm/komeda: pass possible_crtcs as parameter for
>      drm_writeback_connector
>    drm/vkms: pass possible_crtcs as parameter for drm_writeback_connector
>    drm/vc4: change vc4 driver to use
>      drm_writeback_connector_init_with_encoder()
>    drm/rcar_du: pass possible_crtcs as parameter for
>      drm_writeback_connector
>    drm/malidp: pass possible_crtcs as parameter for
>      drm_writeback_connector

I think we expect that at each commit point the kernel should be 
compilable. Could you please squash patches accordingly?

I'd suggest the following patch sequence:

- Add possible_crtcs to the drm_writeback_connector_init() including all 
the driver changes (all drivers must be compilable, including vc4)
- Add drm_writeback_connector_init_with_encoder()
- Modify vc4 to use new API

WDYT?

> 
>   .../drm/arm/display/komeda/komeda_wb_connector.c   |   3 +-
>   drivers/gpu/drm/arm/malidp_mw.c                    |   5 +-
>   drivers/gpu/drm/drm_writeback.c                    | 144 +++++++++++++++------
>   drivers/gpu/drm/rcar-du/rcar_du_writeback.c        |   5 +-
>   drivers/gpu/drm/vc4/vc4_txp.c                      |  30 ++++-
>   drivers/gpu/drm/vkms/vkms_writeback.c              |   3 +-
>   include/drm/drm_writeback.h                        |  27 +++-
>   7 files changed, 161 insertions(+), 56 deletions(-)
> 


-- 
With best wishes
Dmitry