Re: [PATCH v2 1/2] drm/bridge-connector: reset the HDMI connector state

[Abhinav Kumar <quic_abhinavk@quicinc.com>]

On 6/22/2024 10:40 PM, Dmitry Baryshkov wrote:
> On HDMI connectors which use drm_bridge_connector and DRM_BRIDGE_OP_HDMI
> IGT chokes on the max_bpc property in several kms_properties tests due
> to the the drm_bridge_connector failing to reset HDMI-related
> properties.
> 
> Call __drm_atomic_helper_connector_hdmi_reset() if there is a
> the drm_bridge_connector has bridge_hdmi.
> 
> Note, the __drm_atomic_helper_connector_hdmi_reset() is moved to
> drm_atomic_state_helper.c because drm_bridge_connector.c can not depend
> on DRM_DISPLAY_HDMI_STATE_HELPER. At the same time it is impossible to
> call this function from HDMI bridges, there is is no function that
> corresponds to the drm_connector_funcs::reset().
> 
> Fixes: 6b4468b0c6ba ("drm/bridge-connector: implement glue code for HDMI connector")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>   drivers/gpu/drm/display/drm_hdmi_state_helper.c | 21 ---------------------
>   drivers/gpu/drm/drm_atomic_state_helper.c       | 21 +++++++++++++++++++++
>   drivers/gpu/drm/drm_bridge_connector.c          | 13 ++++++++++++-
>   include/drm/display/drm_hdmi_state_helper.h     |  3 ---
>   include/drm/drm_atomic_state_helper.h           |  2 ++
>   5 files changed, 35 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> index 2dab3ad8ce64..67f39857b0b4 100644
> --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> @@ -8,27 +8,6 @@
>   #include <drm/display/drm_hdmi_helper.h>
>   #include <drm/display/drm_hdmi_state_helper.h>
>   
> -/**
> - * __drm_atomic_helper_connector_hdmi_reset() - Initializes all HDMI @drm_connector_state resources
> - * @connector: DRM connector
> - * @new_conn_state: connector state to reset
> - *
> - * Initializes all HDMI resources from a @drm_connector_state without
> - * actually allocating it. This is useful for HDMI drivers, in
> - * combination with __drm_atomic_helper_connector_reset() or
> - * drm_atomic_helper_connector_reset().
> - */
> -void __drm_atomic_helper_connector_hdmi_reset(struct drm_connector *connector,
> -					      struct drm_connector_state *new_conn_state)
> -{
> -	unsigned int max_bpc = connector->max_bpc;
> -
> -	new_conn_state->max_bpc = max_bpc;
> -	new_conn_state->max_requested_bpc = max_bpc;
> -	new_conn_state->hdmi.broadcast_rgb = DRM_HDMI_BROADCAST_RGB_AUTO;
> -}
> -EXPORT_SYMBOL(__drm_atomic_helper_connector_hdmi_reset);
> -
>   static const struct drm_display_mode *
>   connector_state_get_mode(const struct drm_connector_state *conn_state)
>   {
> diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
> index 519228eb1095..1518ada81b45 100644
> --- a/drivers/gpu/drm/drm_atomic_state_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_state_helper.c
> @@ -478,6 +478,27 @@ void drm_atomic_helper_connector_reset(struct drm_connector *connector)
>   }
>   EXPORT_SYMBOL(drm_atomic_helper_connector_reset);
>   
> +/**
> + * __drm_atomic_helper_connector_hdmi_reset() - Initializes all HDMI @drm_connector_state resources
> + * @connector: DRM connector
> + * @new_conn_state: connector state to reset
> + *
> + * Initializes all HDMI resources from a @drm_connector_state without
> + * actually allocating it. This is useful for HDMI drivers, in
> + * combination with __drm_atomic_helper_connector_reset() or
> + * drm_atomic_helper_connector_reset().
> + */
> +void __drm_atomic_helper_connector_hdmi_reset(struct drm_connector *connector,
> +					      struct drm_connector_state *new_conn_state)
> +{
> +	unsigned int max_bpc = connector->max_bpc;
> +
> +	new_conn_state->max_bpc = max_bpc;
> +	new_conn_state->max_requested_bpc = max_bpc;

I understand this is just code propagation but do we need a max_bpc 
local variable?

We can just do

new_conn_state->max_bpc = connector->max_bpc;
new_conn_state->max_requested_bpc = connector->max_bpc;

But apart from that nit, this LGTM.

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>