[PATCH v4 01/16] drm/i915/hdcp: Update CP property in update_pipe

[Ramalingam C]

On 2020-10-27 at 22:11:53 +0530, Anshuman Gupta wrote:
> When crtc state need_modeset is true it is not necessary
> it is going to be a real modeset, it can turns to be a
> fastset instead of modeset.
> This turns content protection property to be DESIRED and hdcp
> update_pipe left with property to be in DESIRED state but
> actual hdcp->value was ENABLED.
> 
> This issue is caught with DP MST setup, where we have multiple
> connector in same DP_MST topology. When disabling HDCP on one of
> DP MST connector leads to set the crtc state need_modeset to true
> for all other crtc driving the other DP-MST topology connectors.
> This turns up other DP MST connectors CP property to be DESIRED
> despite the actual hdcp->value is ENABLED.
> Above scenario fails the DP MST HDCP IGT test, disabling HDCP on
> one MST stream should not cause to disable HDCP on another MST
> stream on same DP MST topology.
> 
> v2:
> Fix WARN_ON(connector->base.registration_state == DRM_CONNECTOR_REGISTERED)
> v3:
> Commit log improvement. [Uma]
> Added a comment before scheduling prop_work. [Uma]
> 
> Fixes: 33f9a623bfc6 ("drm/i915/hdcp: Update CP as per the kernel internal state")
> Cc: Ramalingam C <ramalingam.c at intel.com>
> Signed-off-by: Anshuman Gupta <anshuman.gupta at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_hdcp.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index b2a4bbcfdcd2..eee8263405b9 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -2221,6 +2221,14 @@ void intel_hdcp_update_pipe(struct intel_atomic_state *state,
>  		desired_and_not_enabled =
>  			hdcp->value != DRM_MODE_CONTENT_PROTECTION_ENABLED;
>  		mutex_unlock(&hdcp->mutex);
> +		/*
> +		 * If HDCP already ENABLED and CP property is DESIRED, schedule
> +		 * prop_work to update correct CP property to user space.
> +		 */
> +		if (!desired_and_not_enabled && !content_protection_type_changed) {
> +			drm_connector_get(&connector->base);
Sorry for late review.

why do we need this? and where do we release the connector ref?

-Ram
> +			schedule_work(&hdcp->prop_work);
> +		}
>  	}
>  
>  	if (desired_and_not_enabled || content_protection_type_changed)
> -- 
> 2.26.2
>