Re: [PATCH v7 10/11] drm/hdcp: update content protection property with uevent

[Ramalingam C <ramalingam.c@intel.com>]

On 2019-07-04 at 14:14:19 +0300, Pekka Paalanen wrote:
> On Tue,  7 May 2019 21:57:44 +0530
> Ramalingam C <ramalingam.c@intel.com> wrote:
> 
> > drm function is defined and exported to update a connector's
> > content protection property state and to generate a uevent along
> > with it.
> > 
> > Need ACK for the uevent from userspace consumer.
> > 
> > v2:
> >   Update only when state is different from old one.
> > v3:
> >   KDoc is added [Daniel]
> > 
> > Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> > Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > ---
> >  drivers/gpu/drm/drm_hdcp.c | 32 ++++++++++++++++++++++++++++++++
> >  include/drm/drm_hdcp.h     |  2 ++
> >  2 files changed, 34 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_hdcp.c b/drivers/gpu/drm/drm_hdcp.c
> > index 75402463466b..f29b7abda51f 100644
> > --- a/drivers/gpu/drm/drm_hdcp.c
> > +++ b/drivers/gpu/drm/drm_hdcp.c
> > @@ -372,6 +372,10 @@ DRM_ENUM_NAME_FN(drm_get_hdcp_content_type_name,
> >   *
> >   * The content protection will be set to &drm_connector_state.content_protection
> >   *
> > + * When kernel triggered content protection state change like DESIRED->ENABLED
> > + * and ENABLED->DESIRED, will use drm_hdcp_update_content_protection() to update
> > + * the content protection state of a connector.
> > + *
> >   * Returns:
> >   * Zero on success, negative errno on failure.
> >   */
> > @@ -412,3 +416,31 @@ int drm_connector_attach_content_protection_property(
> >  	return 0;
> >  }
> >  EXPORT_SYMBOL(drm_connector_attach_content_protection_property);
> > +
> > +/**
> > + * drm_hdcp_update_content_protection - Updates the content protection state
> > + * of a connector
> > + *
> > + * @connector: drm_connector on which content protection state needs an update
> > + * @val: New state of the content protection property
> > + *
> > + * This function can be used by display drivers, to update the kernel triggered
> > + * content protection state change of a drm_connector. This function update the
> > + * new state of the property into the connector's state and generate an uevent
> > + * to notify the userspace.
> > + */
> > +void drm_hdcp_update_content_protection(struct drm_connector *connector,
> > +					u64 val)
> > +{
> 
> Hi,
> 
> don't you need to ensure that 'val' cannot be UNDESIRED?
> 
> > +	struct drm_device *dev = connector->dev;
> > +	struct drm_connector_state *state = connector->state;
> > +
> > +	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
> > +	if (state->content_protection == val)
when val==UNDESIRED even the state->content_protection also UNDESIRED.
Hence explicit check is not needed here.

-Ram
> > +		return;
> > +
> > +	state->content_protection = val;
> > +	drm_sysfs_connector_status_event(connector,
> > +				 dev->mode_config.content_protection_property);
> > +}
> > +EXPORT_SYMBOL(drm_hdcp_update_content_protection);
> > diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h
> > index 2970abdfaf12..dd864ac9ce85 100644
> > --- a/include/drm/drm_hdcp.h
> > +++ b/include/drm/drm_hdcp.h
> > @@ -292,4 +292,6 @@ bool drm_hdcp_check_ksvs_revoked(struct drm_device *dev,
> >  				 u8 *ksvs, u32 ksv_count);
> >  int drm_connector_attach_content_protection_property(
> >  		struct drm_connector *connector, bool hdcp_content_type);
> > +void drm_hdcp_update_content_protection(struct drm_connector *connector,
> > +					u64 val);
> >  #endif
> 
> This patch is missing all UAPI documentation.
> 
> Particularly important is the detail that the kernel will not send an
> event corresponding to userspace explicitly setting "Content
> Protection" to "Undesired". That is what you explained to me in the
> Weston MR !48, but I don't actually see it in the code here. It would
> be best to enforce that in the shared DRM code.
> 
> 
> Thanks,
> pq


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