On Tue, 2021-05-25 at 10:59 +1000, Sam McNally wrote:
> With DP v2.0 errata E5, CEC tunneling can be supported through an MST
> topology.
>
> When tunneling CEC through an MST port, CEC IRQs are delivered via a
> sink event notify message; when a sink event notify message is received,
> trigger CEC IRQ handling - ESI1 is not used for remote CEC IRQs so its
> value is not checked.
>
> Register and unregister for all MST connectors, ensuring their
> drm_dp_aux_cec struct won't be accessed uninitialized.
>
> Reviewed-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
> Signed-off-by: Sam McNally <sammc@xxxxxxxxxxxx>
> ---
>
> (no changes since v4)
>
> Changes in v4:
> - Removed use of work queues
> - Updated checks of aux.transfer to accept aux.is_remote
>
> Changes in v3:
> - Fixed whitespace in drm_dp_cec_mst_irq_work()
> - Moved drm_dp_cec_mst_set_edid_work() with the other set_edid functions
>
> Changes in v2:
> - Used aux->is_remote instead of aux->cec.is_mst, removing the need for
> the previous patch in the series
> - Added a defensive check for null edid in the deferred set_edid work,
> in case the edid is no longer valid at that point
>
> drivers/gpu/drm/drm_dp_cec.c | 20 ++++++++++++++++----
> drivers/gpu/drm/drm_dp_mst_topology.c | 24 ++++++++++++++++++++++++
> 2 files changed, 40 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_dp_cec.c b/drivers/gpu/drm/drm_dp_cec.c
> index 3ab2609f9ec7..1abd3f4654dc 100644
> --- a/drivers/gpu/drm/drm_dp_cec.c
> +++ b/drivers/gpu/drm/drm_dp_cec.c
> @@ -14,6 +14,7 @@
> #include <drm/drm_connector.h>
> #include <drm/drm_device.h>
> #include <drm/drm_dp_helper.h>
> +#include <drm/drm_dp_mst_helper.h>
>
> /*
> * Unfortunately it turns out that we have a chicken-and-egg situation
> @@ -245,13 +246,22 @@ void drm_dp_cec_irq(struct drm_dp_aux *aux)
> int ret;
>
> /* No transfer function was set, so not a DP connector */
> - if (!aux->transfer)
> + if (!aux->transfer && !aux->is_remote)
> return;
>
> mutex_lock(&aux->cec.lock);
> if (!aux->cec.adap)
> goto unlock;
>
> + if (aux->is_remote) {
> + /*
> + * For remote connectors, CEC IRQ is triggered by an
> explicit
> + * message so ESI1 is not involved.
> + */
> + drm_dp_cec_handle_irq(aux);
> + goto unlock;
> + }
> +
> ret = drm_dp_dpcd_readb(aux, DP_DEVICE_SERVICE_IRQ_VECTOR_ESI1,
> &cec_irq);
> if (ret < 0 || !(cec_irq & DP_CEC_IRQ))
> @@ -307,7 +317,7 @@ void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const
> struct edid *edid)
> u8 cap;
>
> /* No transfer function was set, so not a DP connector */
> - if (!aux->transfer)
> + if (!aux->transfer && !aux->is_remote)
> return;
>
> #ifndef CONFIG_MEDIA_CEC_RC
> @@ -375,6 +385,7 @@ void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const
> struct edid *edid)
> unlock:
> mutex_unlock(&aux->cec.lock);
> }
> +
> EXPORT_SYMBOL(drm_dp_cec_set_edid);
probably want to get rid of this whitespace
With that fixed, this is:
Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
>
> /*
> @@ -383,7 +394,7 @@ EXPORT_SYMBOL(drm_dp_cec_set_edid);
> void drm_dp_cec_unset_edid(struct drm_dp_aux *aux)
> {
> /* No transfer function was set, so not a DP connector */
> - if (!aux->transfer)
> + if (!aux->transfer && !aux->is_remote)
> return;
>
> cancel_delayed_work_sync(&aux->cec.unregister_work);
> @@ -393,6 +404,7 @@ void drm_dp_cec_unset_edid(struct drm_dp_aux *aux)
> goto unlock;
>
> cec_phys_addr_invalidate(aux->cec.adap);
> +
> /*
> * We're done if we want to keep the CEC device
> * (drm_dp_cec_unregister_delay is >= NEVER_UNREG_DELAY) or if the
> @@ -428,7 +440,7 @@ void drm_dp_cec_register_connector(struct drm_dp_aux
> *aux,
> struct drm_connector *connector)
> {
> WARN_ON(aux->cec.adap);
> - if (WARN_ON(!aux->transfer))
> + if (WARN_ON(!aux->transfer && !aux->is_remote))
> return;
> aux->cec.connector = connector;
> INIT_DELAYED_WORK(&aux->cec.unregister_work,
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 29aad3b6b31a..5612caf9fb49 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -2359,6 +2359,8 @@ static void build_mst_prop_path(const struct
> drm_dp_mst_branch *mstb,
> int drm_dp_mst_connector_late_register(struct drm_connector *connector,
> struct drm_dp_mst_port *port)
> {
> + drm_dp_cec_register_connector(&port->aux, connector);
> +
> drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
> port->aux.name, connector->kdev->kobj.name);
>
> @@ -2382,6 +2384,8 @@ void drm_dp_mst_connector_early_unregister(struct
> drm_connector *connector,
> drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
> port->aux.name, connector->kdev->kobj.name);
> drm_dp_aux_unregister_devnode(&port->aux);
> +
> + drm_dp_cec_unregister_connector(&port->aux);
> }
> EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
>
> @@ -2682,6 +2686,21 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch
> *mstb,
> queue_work(system_long_wq, &mstb->mgr->work);
> }
>
> +static void
> +drm_dp_mst_handle_sink_event(struct drm_dp_mst_branch *mstb,
> + struct drm_dp_sink_event_notify *sink_event)
> +{
> + struct drm_dp_mst_port *port;
> +
> + if (sink_event->event_id & DP_SINK_EVENT_CEC_IRQ_EVENT) {
> + port = drm_dp_get_port(mstb, sink_event->port_number);
> + if (port) {
> + drm_dp_cec_irq(&port->aux);
> + drm_dp_mst_topology_put_port(port);
> + }
> + }
> +}
> +
> static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct
> drm_dp_mst_topology_mgr *mgr,
> u8 lct, u8
> *rad)
> {
> @@ -4170,6 +4189,8 @@ drm_dp_mst_process_up_req(struct
> drm_dp_mst_topology_mgr *mgr,
> if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
> drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
> hotplug = true;
> + } else if (msg->req_type == DP_SINK_EVENT_NOTIFY) {
> + drm_dp_mst_handle_sink_event(mstb, &msg->u.sink_event);
> }
>
> drm_dp_mst_topology_put_mstb(mstb);
> @@ -4362,6 +4383,8 @@ drm_dp_mst_detect_port(struct drm_connector
> *connector,
> break;
> }
> out:
> + if (ret != connector_status_connected)
> + drm_dp_cec_unset_edid(&port->aux);
> drm_dp_mst_topology_put_port(port);
> return ret;
> }
> @@ -4392,6 +4415,7 @@ struct edid *drm_dp_mst_get_edid(struct drm_connector
> *connector, struct drm_dp_
> edid = drm_get_edid(connector, &port->aux.ddc);
> }
> port->has_audio = drm_detect_monitor_audio(edid);
> + drm_dp_cec_set_edid(&port->aux, edid);
> drm_dp_mst_topology_put_port(port);
> return edid;
> }
--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat
