[PATCH 1/4] drm/sysfs: introduce drm_sysfs_connector_hotplug_event

[Jani Nikula]

On Wed, 09 Jun 2021, Simon Ser <contact at emersion.fr> wrote:
> This function sends a hotplug uevent with a CONNECTOR property.
>
> Signed-off-by: Simon Ser <contact at emersion.fr>
> ---
>  drivers/gpu/drm/drm_sysfs.c | 25 +++++++++++++++++++++++++
>  include/drm/drm_sysfs.h     |  1 +
>  2 files changed, 26 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
> index 968a9560b4aa..6b52a53c0c3e 100644
> --- a/drivers/gpu/drm/drm_sysfs.c
> +++ b/drivers/gpu/drm/drm_sysfs.c
> @@ -343,6 +343,31 @@ void drm_sysfs_hotplug_event(struct drm_device *dev)
>  }
>  EXPORT_SYMBOL(drm_sysfs_hotplug_event);
>  
> +/**
> + * drm_sysfs_connector_hotplug_event - generate a DRM uevent for any connector
> + * change
> + * @connector: connector which has changed
> + *
> + * Send a uevent for the DRM connector specified by @connector. This will send
> + * a uevent with the properties HOTPLUG=1 and CONNECTOR.
> + */
> +void drm_sysfs_connector_hotplug_event(struct drm_connector *connector)
> +{
> +	struct drm_device *dev = connector->dev;
> +	char hotplug_str[] = "HOTPLUG=1", conn_id[21];
> +	char *envp[] = { hotplug_str, conn_id, NULL };
> +
> +	snprintf(conn_id, ARRAY_SIZE(conn_id),

Semantically should be sizeof(conn_id) though the result is the same. (I
guess this is copy-paste from drm_sysfs_connector_status_event().)

> +		 "CONNECTOR=%u", connector->base.id);
> +
> +	drm_dbg(connector->dev,

drm_dbg_kms?

> +		"generating hotplug event for [CONNECTOR:%d:%s]\n",
> +		connector->base.id, connector->name);

A matter of taste, but seems like in a lot of places we tend to stick
the [CONNECTOR:%d:%s] at the beginning of the string. So if you have
back-to-back messages related to the same connector, they get aligned
and are easy to spot.

BR,
Jani.

> +
> +	kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
> +}
> +EXPORT_SYMBOL(drm_sysfs_connector_hotplug_event);
> +
>  /**
>   * drm_sysfs_connector_status_event - generate a DRM uevent for connector
>   * property status change
> diff --git a/include/drm/drm_sysfs.h b/include/drm/drm_sysfs.h
> index d454ef617b2c..6273cac44e47 100644
> --- a/include/drm/drm_sysfs.h
> +++ b/include/drm/drm_sysfs.h
> @@ -11,6 +11,7 @@ int drm_class_device_register(struct device *dev);
>  void drm_class_device_unregister(struct device *dev);
>  
>  void drm_sysfs_hotplug_event(struct drm_device *dev);
> +void drm_sysfs_connector_hotplug_event(struct drm_connector *connector);
>  void drm_sysfs_connector_status_event(struct drm_connector *connector,
>  				      struct drm_property *property);
>  #endif

-- 
Jani Nikula, Intel Open Source Graphics Center