Re: [PATCH v7 drm-dp 5/9] drm/hisilicon/hibmc: Getting connector info and EDID by using AUX channel

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 19 Mar 2025, Yongbang Shi <shiyongbang@huawei.com> wrote:
> From: Baihan Li <libaihan@huawei.com>
>
> Add registering drm_aux and use it to get connector edid with drm
> functions. Add ddc channel in connector initialization to put drm_aux
> in drm_connector.
>
> Signed-off-by: Baihan Li <libaihan@huawei.com>
> Signed-off-by: Yongbang Shi <shiyongbang@huawei.com>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
> ChangeLog:
> v6 -> v7:
>   - add if statement about drm aux in hibmc_dp_connector_get_modes(), suggested by Jani Nikula

I don't understand this, and I did not suggest such a thing.

BR,
Jani.


> v5 -> v6:
>   - move the detect_ctx() to the patch 7/9.
> v2 -> v3:
>   - Capitalized EDID and AUX, suggested by Dmitry Baryshkov.
> v1 -> v2:
>   - deleting type conversion, suggested by Dmitry Baryshkov.
>   - deleting hibmc_dp_connector_get_modes() and using drm_connector_helper_get_modes(), suggested by Dmitry Baryshkov.
> ---
>  drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c   |  3 +-
>  .../gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c    | 35 ++++++++++++++++---
>  .../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h   |  5 +++
>  3 files changed, 37 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c
> index ded9e7ce887a..e0bb9b14d9d8 100644
> --- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c
> @@ -161,7 +161,8 @@ void hibmc_dp_aux_init(struct hibmc_dp *dp)
>  				 HIBMC_DP_MIN_PULSE_NUM);
>  
>  	dp->aux.transfer = hibmc_dp_aux_xfer;
> -	dp->aux.is_remote = 0;
> +	dp->aux.name = kasprintf(GFP_KERNEL, "HIBMC DRM dp aux");
> +	dp->aux.drm_dev = dp->drm_dev;
>  	drm_dp_aux_init(&dp->aux);
>  	dp->dp_dev->aux = &dp->aux;
>  }
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
> index 603d6b198a54..0256724d8b9b 100644
> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
> @@ -15,11 +15,20 @@
>  
>  static int hibmc_dp_connector_get_modes(struct drm_connector *connector)
>  {
> +	struct hibmc_dp *dp = to_hibmc_dp(connector);
> +	const struct drm_edid *drm_edid;
>  	int count;
>  
> -	count = drm_add_modes_noedid(connector, connector->dev->mode_config.max_width,
> -				     connector->dev->mode_config.max_height);
> -	drm_set_preferred_mode(connector, 1024, 768); // temporary implementation
> +	if (!dp->aux.name)
> +		return 0;
> +
> +	drm_edid = drm_edid_read_ddc(connector, &dp->aux.ddc);
> +
> +	drm_edid_connector_update(connector, drm_edid);
> +
> +	count = drm_edid_connector_add_modes(connector);
> +
> +	drm_edid_free(drm_edid);
>  
>  	return count;
>  }
> @@ -28,12 +37,28 @@ static const struct drm_connector_helper_funcs hibmc_dp_conn_helper_funcs = {
>  	.get_modes = hibmc_dp_connector_get_modes,
>  };
>  
> +static int hibmc_dp_late_register(struct drm_connector *connector)
> +{
> +	struct hibmc_dp *dp = to_hibmc_dp(connector);
> +
> +	return drm_dp_aux_register(&dp->aux);
> +}
> +
> +static void hibmc_dp_early_unregister(struct drm_connector *connector)
> +{
> +	struct hibmc_dp *dp = to_hibmc_dp(connector);
> +
> +	drm_dp_aux_unregister(&dp->aux);
> +}
> +
>  static const struct drm_connector_funcs hibmc_dp_conn_funcs = {
>  	.reset = drm_atomic_helper_connector_reset,
>  	.fill_modes = drm_helper_probe_single_connector_modes,
>  	.destroy = drm_connector_cleanup,
>  	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
>  	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> +	.late_register = hibmc_dp_late_register,
> +	.early_unregister = hibmc_dp_early_unregister,
>  };
>  
>  static inline int hibmc_dp_prepare(struct hibmc_dp *dp, struct drm_display_mode *mode)
> @@ -103,8 +128,8 @@ int hibmc_dp_init(struct hibmc_drm_private *priv)
>  
>  	drm_encoder_helper_add(encoder, &hibmc_dp_encoder_helper_funcs);
>  
> -	ret = drm_connector_init(dev, connector, &hibmc_dp_conn_funcs,
> -				 DRM_MODE_CONNECTOR_DisplayPort);
> +	ret = drm_connector_init_with_ddc(dev, connector, &hibmc_dp_conn_funcs,
> +					  DRM_MODE_CONNECTOR_DisplayPort, &dp->aux.ddc);
>  	if (ret) {
>  		drm_err(dev, "init dp connector failed: %d\n", ret);
>  		return ret;
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
> index d982f1e4b958..3ddd71aada66 100644
> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
> @@ -47,6 +47,11 @@ static inline struct hibmc_vdac *to_hibmc_vdac(struct drm_connector *connector)
>  	return container_of(connector, struct hibmc_vdac, connector);
>  }
>  
> +static inline struct hibmc_dp *to_hibmc_dp(struct drm_connector *connector)
> +{
> +	return container_of(connector, struct hibmc_dp, connector);
> +}
> +
>  static inline struct hibmc_drm_private *to_hibmc_drm_private(struct drm_device *dev)
>  {
>  	return container_of(dev, struct hibmc_drm_private, dev);

-- 
Jani Nikula, Intel