Re: [PATCH 4/5] drm_dp_cec: add plumbing in preparation for MST support

From: Lyude Paul
Date: Tue Sep 01 2020 - 14:13:03 EST


Super minor nitpicks:

On Tue, 2020-09-01 at 16:22 +1000, Sam McNally wrote:
> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> [sammc@xxxxxxxxxxxx:
> - rebased
> - removed polling-related changes
> - moved the calls to drm_dp_cec_(un)set_edid() into the next patch
> ]
> Signed-off-by: Sam McNally <sammc@xxxxxxxxxxxx>
> ---
>
> .../display/amdgpu_dm/amdgpu_dm_mst_types.c | 2 +-
> drivers/gpu/drm/drm_dp_cec.c | 22 ++++++++++---------
> drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
> drivers/gpu/drm/nouveau/nouveau_connector.c | 2 +-
> include/drm/drm_dp_helper.h | 6 +++--
> 5 files changed, 19 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> index 461fa4da0a34..6e7075893ec9 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> @@ -419,7 +419,7 @@ void amdgpu_dm_initialize_dp_connector(struct
> amdgpu_display_manager *dm,
>
> drm_dp_aux_init(&aconnector->dm_dp_aux.aux);
> drm_dp_cec_register_connector(&aconnector->dm_dp_aux.aux,
> - &aconnector->base);
> + &aconnector->base, false);
>
> if (aconnector->base.connector_type == DRM_MODE_CONNECTOR_eDP)
> return;
> diff --git a/drivers/gpu/drm/drm_dp_cec.c b/drivers/gpu/drm/drm_dp_cec.c
> index 3ab2609f9ec7..04ab7b88055c 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
> @@ -338,8 +339,6 @@ void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const
> struct edid *edid)
> if (aux->cec.adap) {
> if (aux->cec.adap->capabilities == cec_caps &&
> aux->cec.adap->available_log_addrs == num_las) {
> - /* Unchanged, so just set the phys addr */
> - cec_s_phys_addr_from_edid(aux->cec.adap, edid);
> goto unlock;
> }

May as well drop the braces here

> /*
> @@ -364,15 +363,16 @@ void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const
> struct edid *edid)
> if (cec_register_adapter(aux->cec.adap, connector->dev->dev)) {
> cec_delete_adapter(aux->cec.adap);
> aux->cec.adap = NULL;
> - } else {
> - /*
> - * Update the phys addr for the new CEC adapter. When called
> - * from drm_dp_cec_register_connector() edid == NULL, so in
> - * that case the phys addr is just invalidated.
> - */
> - cec_s_phys_addr_from_edid(aux->cec.adap, edid);
> }
> unlock:
> + /*
> + * Update the phys addr for the new CEC adapter. When called
> + * from drm_dp_cec_register_connector() edid == NULL, so in
> + * that case the phys addr is just invalidated.
> + */
> + if (aux->cec.adap && edid) {
> + cec_s_phys_addr_from_edid(aux->cec.adap, edid);
> + }

And here

> mutex_unlock(&aux->cec.lock);
> }
> EXPORT_SYMBOL(drm_dp_cec_set_edid);
> @@ -418,6 +418,7 @@ EXPORT_SYMBOL(drm_dp_cec_unset_edid);
> * drm_dp_cec_register_connector() - register a new connector
> * @aux: DisplayPort AUX channel
> * @connector: drm connector
> + * @is_mst: set to true if this is an MST branch
> *
> * A new connector was registered with associated CEC adapter name and
> * CEC adapter parent device. After registering the name and parent
> @@ -425,12 +426,13 @@ EXPORT_SYMBOL(drm_dp_cec_unset_edid);
> * CEC and to register a CEC adapter if that is the case.
> */
> void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> - struct drm_connector *connector)
> + struct drm_connector *connector, bool is_mst)
> {
> WARN_ON(aux->cec.adap);
> if (WARN_ON(!aux->transfer))
> return;
> aux->cec.connector = connector;
> + aux->cec.is_mst = is_mst;

Also JFYI, you can also check aux->is_remote, but maybe you've got another
reason for copying this here

Either way:

Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>

...Also, maybe this is just a coincidence - but do I know your name from
somewhere? Perhaps an IRC community from long ago?

> INIT_DELAYED_WORK(&aux->cec.unregister_work,
> drm_dp_cec_unregister_work);
> }
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 82b9de274f65..744cb55572f9 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -6261,7 +6261,7 @@ intel_dp_connector_register(struct drm_connector
> *connector)
> intel_dp->aux.dev = connector->kdev;
> ret = drm_dp_aux_register(&intel_dp->aux);
> if (!ret)
> - drm_dp_cec_register_connector(&intel_dp->aux, connector);
> + drm_dp_cec_register_connector(&intel_dp->aux, connector, false);
> return ret;
> }
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c
> b/drivers/gpu/drm/nouveau/nouveau_connector.c
> index 49dd0cbc332f..671a70e95cd1 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_connector.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
> @@ -1414,7 +1414,7 @@ nouveau_connector_create(struct drm_device *dev,
> switch (type) {
> case DRM_MODE_CONNECTOR_DisplayPort:
> case DRM_MODE_CONNECTOR_eDP:
> - drm_dp_cec_register_connector(&nv_connector->aux, connector);
> + drm_dp_cec_register_connector(&nv_connector->aux, connector,
> false);
> break;
> }
>
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 85513eeb2196..12bca1b9512b 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -1495,12 +1495,14 @@ struct drm_connector;
> * @lock: mutex protecting this struct
> * @adap: the CEC adapter for CEC-Tunneling-over-AUX support.
> * @connector: the connector this CEC adapter is associated with
> + * @is_mst: this is an MST branch
> * @unregister_work: unregister the CEC adapter
> */
> struct drm_dp_aux_cec {
> struct mutex lock;
> struct cec_adapter *adap;
> struct drm_connector *connector;
> + bool is_mst;
> struct delayed_work unregister_work;
> };
>
> @@ -1746,7 +1748,7 @@ drm_dp_has_quirk(const struct drm_dp_desc *desc, u32
> edid_quirks,
> #ifdef CONFIG_DRM_DP_CEC
> void drm_dp_cec_irq(struct drm_dp_aux *aux);
> void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> - struct drm_connector *connector);
> + struct drm_connector *connector, bool
> is_mst);
> void drm_dp_cec_unregister_connector(struct drm_dp_aux *aux);
> void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const struct edid *edid);
> void drm_dp_cec_unset_edid(struct drm_dp_aux *aux);
> @@ -1757,7 +1759,7 @@ static inline void drm_dp_cec_irq(struct drm_dp_aux
> *aux)
>
> static inline void
> drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> - struct drm_connector *connector)
> + struct drm_connector *connector, bool is_mst)
> {
> }
>
--
Sincerely,
Lyude Paul (she/her)
Software Engineer at Red Hat