Re: [PATCH v3 10/10] drm/i915: uevent for HDCP status change

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Mar 22, 2019 at 06:14:48AM +0530, Ramalingam C wrote:
> Invoking the uevent generator for the content protection property state
> change of a connector. This helps the userspace to detect the new state
> change without polling the property val.
> 
> Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_hdcp.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
> index 1eea553cdf81..1c38026f4de7 100644
> --- a/drivers/gpu/drm/i915/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/intel_hdcp.c
> @@ -8,6 +8,7 @@
>  
>  #include <drm/drm_hdcp.h>
>  #include <drm/i915_component.h>
> +#include <drm/drm_sysfs.h>
>  #include <linux/i2c.h>
>  #include <linux/random.h>
>  #include <linux/component.h>
> @@ -19,6 +20,14 @@
>  #define ENCRYPT_STATUS_CHANGE_TIMEOUT_MS	50
>  #define HDCP2_LC_RETRY_CNT			3
>  
> +static inline
> +void intel_hdcp_state_change_event(struct drm_connector *connector)
> +{
> +	struct drm_property *property = connector->content_protection_property;
> +
> +	drm_sysfs_connector_status_event(connector, property);
> +}
> +
>  static
>  bool intel_hdcp_is_ksv_valid(u8 *ksv)
>  {
> @@ -943,6 +952,7 @@ static void intel_hdcp_prop_work(struct work_struct *work)
>  	if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
>  		state = connector->base.state;
>  		state->content_protection = hdcp->value;
> +		intel_hdcp_state_change_event(&connector->base);

I think it'd be good to have a helper to update both
state->content_protection and send out the event. Locking is a bit
complicated, so we also need a lockdep assert to make sure
dev->mode_config.connection_mutex is held.

That way I hope that any update in the property will actually result in
the event being sent out, and not accidentally forgotten.

>  	}
>  
>  	mutex_unlock(&hdcp->mutex);
> @@ -2206,6 +2216,7 @@ int intel_hdcp_disable(struct intel_connector *connector)
>  			ret = _intel_hdcp2_disable(connector);
>  		else if (hdcp->hdcp_encrypted)
>  			ret = _intel_hdcp_disable(connector);
> +		intel_hdcp_state_change_event(&connector->base);

Why do we need this here? We don't update the property here ...
-Daniel

>  	}
>  
>  	mutex_unlock(&hdcp->mutex);
> -- 
> 2.19.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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