Re: [PATCH v7 drm-dp 5/9] drm/hisilicon/hibmc: Getting connector info and EDID by using AUX channel

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 24 Mar 2025, Yongbang Shi <shiyongbang@huawei.com> wrote:
>> On Wed, 19 Mar 2025, Yongbang Shi <shiyongbang@huawei.com> wrote:
>>> From: Baihan Li <libaihan@huawei.com>
>>>
>>> Add registering drm_aux and use it to get connector edid with drm
>>> functions. Add ddc channel in connector initialization to put drm_aux
>>> in drm_connector.
>>>
>>> Signed-off-by: Baihan Li <libaihan@huawei.com>
>>> Signed-off-by: Yongbang Shi <shiyongbang@huawei.com>
>>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>>> ---
>>> ChangeLog:
>>> v6 -> v7:
>>>    - add if statement about drm aux in hibmc_dp_connector_get_modes(), suggested by Jani Nikula
>> I don't understand this, and I did not suggest such a thing.
>>
>> BR,
>> Jani.
>>
> Hi Jani,
>
> Is the modification of v8 correct?

I never received that for whatever reason.

>
>
>>> v5 -> v6:
>>>    - move the detect_ctx() to the patch 7/9.
>>> v2 -> v3:
>>>    - Capitalized EDID and AUX, suggested by Dmitry Baryshkov.
>>> v1 -> v2:
>>>    - deleting type conversion, suggested by Dmitry Baryshkov.
>>>    - deleting hibmc_dp_connector_get_modes() and using drm_connector_helper_get_modes(), suggested by Dmitry Baryshkov.
>>> ---
>>>   drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c   |  3 +-
>>>   .../gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c    | 35 ++++++++++++++++---
>>>   .../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h   |  5 +++
>>>   3 files changed, 37 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c
>>> index ded9e7ce887a..e0bb9b14d9d8 100644
>>> --- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c
>>> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c
>>> @@ -161,7 +161,8 @@ void hibmc_dp_aux_init(struct hibmc_dp *dp)
>>>   				 HIBMC_DP_MIN_PULSE_NUM);
>>>   
>>>   	dp->aux.transfer = hibmc_dp_aux_xfer;
>>> -	dp->aux.is_remote = 0;
>>> +	dp->aux.name = kasprintf(GFP_KERNEL, "HIBMC DRM dp aux");
>>> +	dp->aux.drm_dev = dp->drm_dev;
>>>   	drm_dp_aux_init(&dp->aux);
>>>   	dp->dp_dev->aux = &dp->aux;
>>>   }
>>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
>>> index 603d6b198a54..0256724d8b9b 100644
>>> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
>>> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
>>> @@ -15,11 +15,20 @@
>>>   
>>>   static int hibmc_dp_connector_get_modes(struct drm_connector *connector)
>>>   {
>>> +	struct hibmc_dp *dp = to_hibmc_dp(connector);
>>> +	const struct drm_edid *drm_edid;
>>>   	int count;
>>>   
>>> -	count = drm_add_modes_noedid(connector, connector->dev->mode_config.max_width,
>>> -				     connector->dev->mode_config.max_height);
>>> -	drm_set_preferred_mode(connector, 1024, 768); // temporary implementation
>>> +	if (!dp->aux.name)
>>> +		return 0;
>>> +
>>> +	drm_edid = drm_edid_read_ddc(connector, &dp->aux.ddc);
>>> +
>>> +	drm_edid_connector_update(connector, drm_edid);
>>> +
>>> +	count = drm_edid_connector_add_modes(connector);
>>> +
>>> +	drm_edid_free(drm_edid);
>>>   
>>>   	return count;
>>>   }
>>> @@ -28,12 +37,28 @@ static const struct drm_connector_helper_funcs hibmc_dp_conn_helper_funcs = {
>>>   	.get_modes = hibmc_dp_connector_get_modes,
>>>   };
>>>   
>>> +static int hibmc_dp_late_register(struct drm_connector *connector)
>>> +{
>>> +	struct hibmc_dp *dp = to_hibmc_dp(connector);
>>> +
>>> +	return drm_dp_aux_register(&dp->aux);
>>> +}
>>> +
>>> +static void hibmc_dp_early_unregister(struct drm_connector *connector)
>>> +{
>>> +	struct hibmc_dp *dp = to_hibmc_dp(connector);
>>> +
>>> +	drm_dp_aux_unregister(&dp->aux);
>>> +}
>>> +
>>>   static const struct drm_connector_funcs hibmc_dp_conn_funcs = {
>>>   	.reset = drm_atomic_helper_connector_reset,
>>>   	.fill_modes = drm_helper_probe_single_connector_modes,
>>>   	.destroy = drm_connector_cleanup,
>>>   	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
>>>   	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
>>> +	.late_register = hibmc_dp_late_register,
>>> +	.early_unregister = hibmc_dp_early_unregister,
>>>   };
>>>   
>>>   static inline int hibmc_dp_prepare(struct hibmc_dp *dp, struct drm_display_mode *mode)
>>> @@ -103,8 +128,8 @@ int hibmc_dp_init(struct hibmc_drm_private *priv)
>>>   
>>>   	drm_encoder_helper_add(encoder, &hibmc_dp_encoder_helper_funcs);
>>>   
>>> -	ret = drm_connector_init(dev, connector, &hibmc_dp_conn_funcs,
>>> -				 DRM_MODE_CONNECTOR_DisplayPort);
>>> +	ret = drm_connector_init_with_ddc(dev, connector, &hibmc_dp_conn_funcs,
>>> +					  DRM_MODE_CONNECTOR_DisplayPort, &dp->aux.ddc);
>>>   	if (ret) {
>>>   		drm_err(dev, "init dp connector failed: %d\n", ret);
>>>   		return ret;
>>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
>>> index d982f1e4b958..3ddd71aada66 100644
>>> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
>>> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
>>> @@ -47,6 +47,11 @@ static inline struct hibmc_vdac *to_hibmc_vdac(struct drm_connector *connector)
>>>   	return container_of(connector, struct hibmc_vdac, connector);
>>>   }
>>>   
>>> +static inline struct hibmc_dp *to_hibmc_dp(struct drm_connector *connector)
>>> +{
>>> +	return container_of(connector, struct hibmc_dp, connector);
>>> +}
>>> +
>>>   static inline struct hibmc_drm_private *to_hibmc_drm_private(struct drm_device *dev)
>>>   {
>>>   	return container_of(dev, struct hibmc_drm_private, dev);

-- 
Jani Nikula, Intel