[RFC PATCH v2 2/3] drm/bridge: cadence: cdns-mhdp8546*: Change drm_connector from pointer to structure
Jayesh Choudhary
j-choudhary at ti.com
Tue May 27 09:29:39 UTC 2025
Hello Tomi,
On 27/05/25 13:28, Tomi Valkeinen wrote:
> Hi,
>
> On 21/05/2025 10:32, Jayesh Choudhary wrote:
>> After adding DBANC framework, mhdp->connector is not initialised during
>> bridge calls. But the asyncronous work scheduled depends on the connector.
>> We cannot get to drm_atomic_state in these asyncronous calls running on
>> worker threads. So we need to store the data that we need in mhdp bridge
>> structure.
>> Like other bridge drivers, use drm_connector pointer instead of structure
>> and make appropriate changes to the conditionals and assignments related
>> to mhdp->connector.
>> Also, in the atomic enable call, move the connector and connector state
>> calls above, so that we do have a connector before we can retry the
>> asyncronous work in case of any failure.
>>
>
> I don't quite understand this patch. You change the mhdp->connector to a
> pointer, which is set at bridge_enable and cleared at bridge_disable.
> Then you change the "mhdp->connector.dev" checks to "mhdp->connector".
>
> So, now in e.g. cdns_mhdp_fw_cb(), we check for mhdp->connector, which
> is set at bridge_enable(). Can we ever have the bridge enabled before
> the fb has been loaded? What is the check even supposed to do there?
>
> Another in cdns_mhdp_hpd_work(), it checks for mhdp->connector. So...
> HPD code behaves differently based on if the bridge has been enabled or
> not? What is it supposed to do?
>
> Isn't the whole "if (mhdp->connector.dev)" code for the legacy
> non-DRM_BRIDGE_ATTACH_NO_CONNECTOR case?
>
> Tomi
I misinterpreted your comment in v1[0] regarding finding the connector
from the current state in cdns_mhdp_modeset_retry_fn() and I missed
this. I was more focused on finding a connector for that function.
For the current code, in all the conditionals involving mhdp->connector,
we are entering else statements as connector is not initialised.
So I will just drop if statements in cdns_mhdp_fw_cb() and
cdns_mhdp_hpd_work() (like you said, its legacy case) while still having
mhdp->connector as pointer as we need it for
cdns_mhdp_modeset_retry_fn() and in cdns-mhdp8546-hdcp driver.
That should be okay?
[0]:
https://lore.kernel.org/all/e76f94b9-b138-46e7-bb18-b33dd98c9abb@ideasonboard.com/
Warm Regards,
Jayesh
>
>> Fixes: fb43aa0acdfd ("drm: bridge: Add support for Cadence MHDP8546 DPI/DP bridge")
>> Signed-off-by: Jayesh Choudhary <j-choudhary at ti.com>
>> ---
>> .../drm/bridge/cadence/cdns-mhdp8546-core.c | 28 +++++++++----------
>> .../drm/bridge/cadence/cdns-mhdp8546-core.h | 2 +-
>> .../drm/bridge/cadence/cdns-mhdp8546-hdcp.c | 8 +++---
>> 3 files changed, 19 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
>> index 66bd916c2fe9..5388e62f230b 100644
>> --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
>> +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
>> @@ -740,7 +740,7 @@ static void cdns_mhdp_fw_cb(const struct firmware *fw, void *context)
>> bridge_attached = mhdp->bridge_attached;
>> spin_unlock(&mhdp->start_lock);
>> if (bridge_attached) {
>> - if (mhdp->connector.dev)
>> + if (mhdp->connector)
>> drm_kms_helper_hotplug_event(mhdp->bridge.dev);
>> else
>> drm_bridge_hpd_notify(&mhdp->bridge, cdns_mhdp_detect(mhdp));
>> @@ -1759,17 +1759,25 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge *bridge,
>> struct cdns_mhdp_device *mhdp = bridge_to_mhdp(bridge);
>> struct cdns_mhdp_bridge_state *mhdp_state;
>> struct drm_crtc_state *crtc_state;
>> - struct drm_connector *connector;
>> struct drm_connector_state *conn_state;
>> struct drm_bridge_state *new_state;
>> const struct drm_display_mode *mode;
>> u32 resp;
>> - int ret;
>> + int ret = 0;
>>
>> dev_dbg(mhdp->dev, "bridge enable\n");
>>
>> mutex_lock(&mhdp->link_mutex);
>>
>> + mhdp->connector = drm_atomic_get_new_connector_for_encoder(state,
>> + bridge->encoder);
>> + if (WARN_ON(!mhdp->connector))
>> + goto out;
>> +
>> + conn_state = drm_atomic_get_new_connector_state(state, mhdp->connector);
>> + if (WARN_ON(!conn_state))
>> + goto out;
>> +
>> if (mhdp->plugged && !mhdp->link_up) {
>> ret = cdns_mhdp_link_up(mhdp);
>> if (ret < 0)
>> @@ -1789,15 +1797,6 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge *bridge,
>> cdns_mhdp_reg_write(mhdp, CDNS_DPTX_CAR,
>> resp | CDNS_VIF_CLK_EN | CDNS_VIF_CLK_RSTN);
>>
>> - connector = drm_atomic_get_new_connector_for_encoder(state,
>> - bridge->encoder);
>> - if (WARN_ON(!connector))
>> - goto out;
>> -
>> - conn_state = drm_atomic_get_new_connector_state(state, connector);
>> - if (WARN_ON(!conn_state))
>> - goto out;
>> -
>> if (mhdp->hdcp_supported &&
>> mhdp->hw_state == MHDP_HW_READY &&
>> conn_state->content_protection ==
>> @@ -1857,6 +1856,7 @@ static void cdns_mhdp_atomic_disable(struct drm_bridge *bridge,
>> cdns_mhdp_hdcp_disable(mhdp);
>>
>> mhdp->bridge_enabled = false;
>> + mhdp->connector = NULL;
>> cdns_mhdp_reg_read(mhdp, CDNS_DP_FRAMER_GLOBAL_CONFIG, &resp);
>> resp &= ~CDNS_DP_FRAMER_EN;
>> resp |= CDNS_DP_NO_VIDEO_MODE;
>> @@ -2157,7 +2157,7 @@ static void cdns_mhdp_modeset_retry_fn(struct work_struct *work)
>>
>> mhdp = container_of(work, typeof(*mhdp), modeset_retry_work);
>>
>> - conn = &mhdp->connector;
>> + conn = mhdp->connector;
>>
>> /* Grab the locks before changing connector property */
>> mutex_lock(&conn->dev->mode_config.mutex);
>> @@ -2234,7 +2234,7 @@ static void cdns_mhdp_hpd_work(struct work_struct *work)
>> int ret;
>>
>> ret = cdns_mhdp_update_link_status(mhdp);
>> - if (mhdp->connector.dev) {
>> + if (mhdp->connector) {
>> if (ret < 0)
>> schedule_work(&mhdp->modeset_retry_work);
>> else
>> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
>> index bad2fc0c7306..b297db53ba28 100644
>> --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
>> +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
>> @@ -375,7 +375,7 @@ struct cdns_mhdp_device {
>> */
>> struct mutex link_mutex;
>>
>> - struct drm_connector connector;
>> + struct drm_connector *connector;
>> struct drm_bridge bridge;
>>
>> struct cdns_mhdp_link link;
>> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c
>> index 42248f179b69..59f18c3281ef 100644
>> --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c
>> +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c
>> @@ -394,7 +394,7 @@ static int _cdns_mhdp_hdcp_disable(struct cdns_mhdp_device *mhdp)
>> int ret;
>>
>> dev_dbg(mhdp->dev, "[%s:%d] HDCP is being disabled...\n",
>> - mhdp->connector.name, mhdp->connector.base.id);
>> + mhdp->connector->name, mhdp->connector->base.id);
>>
>> ret = cdns_mhdp_hdcp_set_config(mhdp, 0, false);
>>
>> @@ -445,7 +445,7 @@ static int cdns_mhdp_hdcp_check_link(struct cdns_mhdp_device *mhdp)
>>
>> dev_err(mhdp->dev,
>> "[%s:%d] HDCP link failed, retrying authentication\n",
>> - mhdp->connector.name, mhdp->connector.base.id);
>> + mhdp->connector->name, mhdp->connector->base.id);
>>
>> ret = _cdns_mhdp_hdcp_disable(mhdp);
>> if (ret) {
>> @@ -487,13 +487,13 @@ static void cdns_mhdp_hdcp_prop_work(struct work_struct *work)
>> struct cdns_mhdp_device *mhdp = container_of(hdcp,
>> struct cdns_mhdp_device,
>> hdcp);
>> - struct drm_device *dev = mhdp->connector.dev;
>> + struct drm_device *dev = mhdp->connector->dev;
>> struct drm_connector_state *state;
>>
>> drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
>> mutex_lock(&mhdp->hdcp.mutex);
>> if (mhdp->hdcp.value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
>> - state = mhdp->connector.state;
>> + state = mhdp->connector->state;
>> state->content_protection = mhdp->hdcp.value;
>> }
>> mutex_unlock(&mhdp->hdcp.mutex);
>
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