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

[Yongbang Shi <shiyongbang@huawei.com>]

> 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?


>> 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);