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Message-ID: <2f1e64e4-bb37-0cfb-6b3b-3f51fd5faca3@xs4all.nl>
Date: Tue, 8 Sep 2020 10:41:26 +0200
From: Hans Verkuil <hverkuil@...all.nl>
To: Sam McNally <sammc@...omium.org>,
LKML <linux-kernel@...r.kernel.org>
Cc: David Airlie <airlied@...ux.ie>, nouveau@...ts.freedesktop.org,
José Roberto de Souza <jose.souza@...el.com>,
David Francis <David.Francis@....com>,
Rodrigo Siqueira <Rodrigo.Siqueira@....com>,
amd-gfx@...ts.freedesktop.org, Ben Skeggs <bskeggs@...hat.com>,
Wambui Karuga <wambui.karugax@...il.com>,
Thomas Zimmermann <tzimmermann@...e.de>,
Leo Li <sunpeng.li@....com>,
Lucas De Marchi <lucas.demarchi@...el.com>,
intel-gfx@...ts.freedesktop.org,
Gwan-gyeong Mun <gwan-gyeong.mun@...el.com>,
Rodrigo Vivi <rodrigo.vivi@...el.com>,
Mikita Lipski <mikita.lipski@....com>,
Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@...el.com>,
dri-devel@...ts.freedesktop.org,
Manasi Navare <manasi.d.navare@...el.com>,
Alex Deucher <alexander.deucher@....com>,
Christian König <christian.koenig@....com>
Subject: Re: [PATCH 4/5] drm_dp_cec: add plumbing in preparation for MST
support
On 01/09/2020 08:22, Sam McNally wrote:
> From: Hans Verkuil <hans.verkuil@...co.com>
>
> Signed-off-by: Hans Verkuil <hans.verkuil@...co.com>
> [sammc@...omium.org:
> - 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@...omium.org>
> ---
>
> .../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;
> }
> /*
> @@ -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.
> + */
The comment is no longer in sync with the code: if EDID == NULL, then
nothing is done due to the edid check in the 'if' below.
> + if (aux->cec.adap && edid) {
I think this should just be: if (aux->cec.adap)
Also, the {} aren't necessary here.
> + cec_s_phys_addr_from_edid(aux->cec.adap, edid);
> + }
> mutex_unlock(&aux->cec.lock);
> }
> EXPORT_SYMBOL(drm_dp_cec_set_edid);
Frankly, the changes to this function should be dropped completely, from
what I can see they are not necessary. It was done in my original patch
because of the way I handled mst, but you did it differently (and I think
better), so these changes are no longer needed.
I know I am actually commenting on my old patch, but that patch was from a
work-in-progress git branch and was never meant as a 'proper' patch.
However, what complicates matters is that after digging a bit more I discovered
that commit 732300154980 ("drm: Do not call drm_dp_cec_set_edid() while registering
DP connectors") changed drm_dp_cec_register_connector() so that it no longer
calls drm_dp_cec_set_edid(), but the comments there and in this function were
not updated. It would be nice if you can add a patch fixing these outdated
comments.
Regardless of that change in commit 732300154980, the edid pointer can still be
NULL and the existing behavior should be kept (i.e. create a CEC device, but with
an invalid physical address since there is no EDID for some reason).
Regards,
Hans
> @@ -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;
> 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)
> {
> }
>
>
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