diff mbox series

[v1,5/5] drm/msm/dp: move of_dp_aux_populate_bus() to probe for eDP

Message ID 1688773943-3887-6-git-send-email-quic_khsieh@quicinc.com (mailing list archive)
State New, archived
Headers show
Series incorporate pm runtime framework and eDP clean up | expand

Commit Message

Kuogee Hsieh July 7, 2023, 11:52 p.m. UTC
Move of_dp_aux_populate_bus() to dp_display_probe() for eDP
from dp_display_bind() so that probe deferral cases can be
handled effectively

Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
---
 drivers/gpu/drm/msm/dp/dp_aux.c     | 25 ++++++++++++
 drivers/gpu/drm/msm/dp/dp_display.c | 79 +++++++++++++++++++------------------
 2 files changed, 65 insertions(+), 39 deletions(-)

Comments

Dmitry Baryshkov July 8, 2023, 12:32 a.m. UTC | #1
On 08/07/2023 02:52, Kuogee Hsieh wrote:
> Move of_dp_aux_populate_bus() to dp_display_probe() for eDP
> from dp_display_bind() so that probe deferral cases can be
> handled effectively
> 
> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
> ---
>   drivers/gpu/drm/msm/dp/dp_aux.c     | 25 ++++++++++++
>   drivers/gpu/drm/msm/dp/dp_display.c | 79 +++++++++++++++++++------------------
>   2 files changed, 65 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
> index c592064..c1baffb 100644
> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
> @@ -505,6 +505,21 @@ void dp_aux_unregister(struct drm_dp_aux *dp_aux)
>   	drm_dp_aux_unregister(dp_aux);
>   }
>   
> +static int dp_wait_hpd_asserted(struct drm_dp_aux *dp_aux,
> +				 unsigned long wait_us)
> +{
> +	int ret;
> +	struct dp_aux_private *aux;
> +
> +	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
> +
> +	pm_runtime_get_sync(aux->dev);
> +	ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog);
> +	pm_runtime_put_sync(aux->dev);
> +
> +	return ret;
> +}
> +
>   struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
>   			      bool is_edp)
>   {
> @@ -528,6 +543,16 @@ struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
>   	aux->catalog = catalog;
>   	aux->retry_cnt = 0;
>   
> +	/*
> +	 * Use the drm_dp_aux_init() to use the aux adapter
> +	 * before registering aux with the DRM device.
> +	 */
> +	aux->dp_aux.name = "dpu_dp_aux";
> +	aux->dp_aux.dev = dev;
> +	aux->dp_aux.transfer = dp_aux_transfer;
> +	aux->dp_aux.wait_hpd_asserted = dp_wait_hpd_asserted;
> +	drm_dp_aux_init(&aux->dp_aux);
> +
>   	return &aux->dp_aux;
>   }
>   
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index 185f1eb..7ed4bea 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -302,10 +302,6 @@ static int dp_display_bind(struct device *dev, struct device *master,
>   		goto end;
>   	}
>   
> -	pm_runtime_enable(dev);
> -	pm_runtime_set_autosuspend_delay(dev, 1000);
> -	pm_runtime_use_autosuspend(dev);
> -
>   	return 0;
>   end:
>   	return rc;
> @@ -322,8 +318,6 @@ static void dp_display_unbind(struct device *dev, struct device *master,
>   
>   	kthread_stop(dp->ev_tsk);
>   
> -	of_dp_aux_depopulate_bus(dp->aux);
> -
>   	dp_power_client_deinit(dp->power);
>   	dp_unregister_audio_driver(dev, dp->audio);
>   	dp_aux_unregister(dp->aux);
> @@ -1245,6 +1239,29 @@ static const struct msm_dp_desc *dp_display_get_desc(struct platform_device *pde
>   	return NULL;
>   }
>   
> +static void of_dp_aux_depopulate_bus_void(void *data)
> +{
> +	of_dp_aux_depopulate_bus(data);
> +}
> +
> +static int dp_display_auxbus_emulation(struct dp_display_private *dp)

Why is it called emulation?

> +{
> +	struct device *dev = &dp->pdev->dev;
> +	struct device_node *aux_bus;
> +	int ret = 0;
> +
> +	aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
> +
> +	if (aux_bus) {
> +		ret = devm_of_dp_aux_populate_bus(dp->aux, NULL);

And here you missed the whole point of why we have been asking for. 
Please add a sensible `done_probing' callback, which will call 
component_add(). This way the DP component will only be registered when 
the panel has been probed. Keeping us from the component binding retries 
and corresponding side effects.

> +
> +		devm_add_action_or_reset(dev, of_dp_aux_depopulate_bus_void,
> +					 dp->aux);

Useless, it's already handled by the devm_ part of the 
devm_of_dp_aux_populate_bus().

> +	}
> +
> +	return ret;
> +}
> +
>   static int dp_display_probe(struct platform_device *pdev)
>   {
>   	int rc = 0;
> @@ -1290,8 +1307,18 @@ static int dp_display_probe(struct platform_device *pdev)
>   
>   	platform_set_drvdata(pdev, &dp->dp_display);
>   
> +	pm_runtime_enable(&pdev->dev);
> +	pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
> +	pm_runtime_use_autosuspend(&pdev->dev);

Can we have this in probe right from the patch #2?

> +
>   	dp_display_request_irq(dp);
>   
> +	if (dp->dp_display.is_edp) {
> +		rc = dp_display_auxbus_emulation(dp);
> +		if (rc)
> +			DRM_ERROR("eDP aux-bus emulation failed, rc=%d\n", rc);
> +	}
> +
>   	rc = component_add(&pdev->dev, &dp_display_comp_ops);
>   	if (rc) {
>   		DRM_ERROR("component add failed, rc=%d\n", rc);
> @@ -1306,11 +1333,14 @@ static int dp_display_remove(struct platform_device *pdev)
>   	struct dp_display_private *dp = dev_get_dp_display_private(&pdev->dev);
>   
>   	component_del(&pdev->dev, &dp_display_comp_ops);
> -	dp_display_deinit_sub_modules(dp);
> -
>   	platform_set_drvdata(pdev, NULL);
> +
> +	pm_runtime_dont_use_autosuspend(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
>   	pm_runtime_put_sync_suspend(&pdev->dev);
>   
> +	dp_display_deinit_sub_modules(dp);
> +
>   	return 0;
>   }
>   
> @@ -1514,31 +1544,10 @@ void msm_dp_debugfs_init(struct msm_dp *dp_display, struct drm_minor *minor)
>   
>   static int dp_display_get_next_bridge(struct msm_dp *dp)
>   {
> -	int rc;
> +	int rc = 0;
>   	struct dp_display_private *dp_priv;
> -	struct device_node *aux_bus;
> -	struct device *dev;
>   
>   	dp_priv = container_of(dp, struct dp_display_private, dp_display);
> -	dev = &dp_priv->pdev->dev;
> -	aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
> -
> -	if (aux_bus && dp->is_edp) {
> -		/*
> -		 * The code below assumes that the panel will finish probing
> -		 * by the time devm_of_dp_aux_populate_ep_devices() returns.
> -		 * This isn't a great assumption since it will fail if the
> -		 * panel driver is probed asynchronously but is the best we
> -		 * can do without a bigger driver reorganization.
> -		 */
> -		rc = of_dp_aux_populate_bus(dp_priv->aux, NULL);
> -		of_node_put(aux_bus);
> -		if (rc)
> -			goto error;
> -	} else if (dp->is_edp) {
> -		DRM_ERROR("eDP aux_bus not found\n");
> -		return -ENODEV;
> -	}
>   
>   	/*
>   	 * External bridges are mandatory for eDP interfaces: one has to
> @@ -1551,17 +1560,9 @@ static int dp_display_get_next_bridge(struct msm_dp *dp)
>   	if (!dp->is_edp && rc == -ENODEV)
>   		return 0;
>   
> -	if (!rc) {
> +	if (!rc)
>   		dp->next_bridge = dp_priv->parser->next_bridge;
> -		return 0;
> -	}
>   
> -error:
> -	if (dp->is_edp) {
> -		of_dp_aux_depopulate_bus(dp_priv->aux);
> -		dp_display_host_phy_exit(dp_priv);
> -		dp_display_host_deinit(dp_priv);
> -	}
>   	return rc;
>   }
>
Dmitry Baryshkov July 10, 2023, 6:24 p.m. UTC | #2
[Restored CC list]

On Mon, 10 Jul 2023 at 20:08, Kuogee Hsieh <quic_khsieh@quicinc.com> wrote:
>
>
> On 7/7/2023 5:32 PM, Dmitry Baryshkov wrote:
> > On 08/07/2023 02:52, Kuogee Hsieh wrote:
> >> Move of_dp_aux_populate_bus() to dp_display_probe() for eDP
> >> from dp_display_bind() so that probe deferral cases can be
> >> handled effectively
> >>
> >> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
> >> ---
> >>   drivers/gpu/drm/msm/dp/dp_aux.c     | 25 ++++++++++++
> >>   drivers/gpu/drm/msm/dp/dp_display.c | 79
> >> +++++++++++++++++++------------------
> >>   2 files changed, 65 insertions(+), 39 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c
> >> b/drivers/gpu/drm/msm/dp/dp_aux.c
> >> index c592064..c1baffb 100644
> >> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
> >> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
> >> @@ -505,6 +505,21 @@ void dp_aux_unregister(struct drm_dp_aux *dp_aux)
> >>       drm_dp_aux_unregister(dp_aux);
> >>   }
> >>   +static int dp_wait_hpd_asserted(struct drm_dp_aux *dp_aux,
> >> +                 unsigned long wait_us)
> >> +{
> >> +    int ret;
> >> +    struct dp_aux_private *aux;
> >> +
> >> +    aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
> >> +
> >> +    pm_runtime_get_sync(aux->dev);
> >> +    ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog);
> >> +    pm_runtime_put_sync(aux->dev);
> >> +
> >> +    return ret;
> >> +}
> >> +
> >>   struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog
> >> *catalog,
> >>                     bool is_edp)
> >>   {
> >> @@ -528,6 +543,16 @@ struct drm_dp_aux *dp_aux_get(struct device
> >> *dev, struct dp_catalog *catalog,
> >>       aux->catalog = catalog;
> >>       aux->retry_cnt = 0;
> >>   +    /*
> >> +     * Use the drm_dp_aux_init() to use the aux adapter
> >> +     * before registering aux with the DRM device.
> >> +     */
> >> +    aux->dp_aux.name = "dpu_dp_aux";
> >> +    aux->dp_aux.dev = dev;
> >> +    aux->dp_aux.transfer = dp_aux_transfer;
> >> +    aux->dp_aux.wait_hpd_asserted = dp_wait_hpd_asserted;
> >> +    drm_dp_aux_init(&aux->dp_aux);
> >> +
> >>       return &aux->dp_aux;
> >>   }
> >>   diff --git a/drivers/gpu/drm/msm/dp/dp_display.c
> >> b/drivers/gpu/drm/msm/dp/dp_display.c
> >> index 185f1eb..7ed4bea 100644
> >> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> >> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> >> @@ -302,10 +302,6 @@ static int dp_display_bind(struct device *dev,
> >> struct device *master,
> >>           goto end;
> >>       }
> >>   -    pm_runtime_enable(dev);
> >> -    pm_runtime_set_autosuspend_delay(dev, 1000);
> >> -    pm_runtime_use_autosuspend(dev);
> >> -
> >>       return 0;
> >>   end:
> >>       return rc;
> >> @@ -322,8 +318,6 @@ static void dp_display_unbind(struct device *dev,
> >> struct device *master,
> >>         kthread_stop(dp->ev_tsk);
> >>   -    of_dp_aux_depopulate_bus(dp->aux);
> >> -
> >>       dp_power_client_deinit(dp->power);
> >>       dp_unregister_audio_driver(dev, dp->audio);
> >>       dp_aux_unregister(dp->aux);
> >> @@ -1245,6 +1239,29 @@ static const struct msm_dp_desc
> >> *dp_display_get_desc(struct platform_device *pde
> >>       return NULL;
> >>   }
> >>   +static void of_dp_aux_depopulate_bus_void(void *data)
> >> +{
> >> +    of_dp_aux_depopulate_bus(data);
> >> +}
> >> +
> >> +static int dp_display_auxbus_emulation(struct dp_display_private *dp)
> >
> > Why is it called emulation?
> >
> >> +{
> >> +    struct device *dev = &dp->pdev->dev;
> >> +    struct device_node *aux_bus;
> >> +    int ret = 0;
> >> +
> >> +    aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
> >> +
> >> +    if (aux_bus) {
> >> +        ret = devm_of_dp_aux_populate_bus(dp->aux, NULL);
> >
> > And here you missed the whole point of why we have been asking for.
> > Please add a sensible `done_probing' callback, which will call
> > component_add(). This way the DP component will only be registered
> > when the panel has been probed. Keeping us from the component binding
> > retries and corresponding side effects.
> >
> >> +
> >> +        devm_add_action_or_reset(dev, of_dp_aux_depopulate_bus_void,
> >> +                     dp->aux);
> >
> > Useless, it's already handled by the devm_ part of the
> > devm_of_dp_aux_populate_bus().
> >
> >> +    }
> >> +
> >> +    return ret;
> >> +}
> >> +
> >>   static int dp_display_probe(struct platform_device *pdev)
> >>   {
> >>       int rc = 0;
> >> @@ -1290,8 +1307,18 @@ static int dp_display_probe(struct
> >> platform_device *pdev)
> >>         platform_set_drvdata(pdev, &dp->dp_display);
> >>   +    pm_runtime_enable(&pdev->dev);
> >> +    pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
> >> +    pm_runtime_use_autosuspend(&pdev->dev);
> >
> > Can we have this in probe right from the patch #2?
>
> no, at patch#2, devm_of_dp_aux_populate_bus() is done ta bind timing.
>
> The device used by pm_runtime_get_sync() of generic_edp_panel_probe()
> which is derived from devm_of_dp_aux_populate_bus() is different the
> &pdev->dev here.

Excuse me, I don't get your answer. In patch #2 you have added
pm_runtime_enable() / etc to dp_display_bind().
In this patch you are moving these calls to dp_display_probe(). I
think that the latter is a better place for enabling runtime PM and as
such I've asked you to squash this chunk into patch #2.
Why isn't that going to work?

If I'm not mistaken here, the panel's call to pm_runtime_get_sync()
will wake up the panel and all the parent devices, including the DP.
That's what I meant in my comment regarding PM calls in the patch #1.
pm_runtime_get_sync() / resume() / etc. do not only increase the
runtime PM count. They do other things to parent devices, linked
devices, etc.

>
> >
> >> +
> >>       dp_display_request_irq(dp);
> >>   +    if (dp->dp_display.is_edp) {
> >> +        rc = dp_display_auxbus_emulation(dp);
> >> +        if (rc)
> >> +            DRM_ERROR("eDP aux-bus emulation failed, rc=%d\n", rc);
> >> +    }
> >> +
> >>       rc = component_add(&pdev->dev, &dp_display_comp_ops);
> >>       if (rc) {
> >>           DRM_ERROR("component add failed, rc=%d\n", rc);
> >> @@ -1306,11 +1333,14 @@ static int dp_display_remove(struct
> >> platform_device *pdev)
> >>       struct dp_display_private *dp =
> >> dev_get_dp_display_private(&pdev->dev);
> >>         component_del(&pdev->dev, &dp_display_comp_ops);
> >> -    dp_display_deinit_sub_modules(dp);
> >> -
> >>       platform_set_drvdata(pdev, NULL);
> >> +
> >> +    pm_runtime_dont_use_autosuspend(&pdev->dev);
> >> +    pm_runtime_disable(&pdev->dev);
> >>       pm_runtime_put_sync_suspend(&pdev->dev);
> >>   +    dp_display_deinit_sub_modules(dp);
> >> +
> >>       return 0;
> >>   }
> >>   @@ -1514,31 +1544,10 @@ void msm_dp_debugfs_init(struct msm_dp
> >> *dp_display, struct drm_minor *minor)
> >>     static int dp_display_get_next_bridge(struct msm_dp *dp)
> >>   {
> >> -    int rc;
> >> +    int rc = 0;
> >>       struct dp_display_private *dp_priv;
> >> -    struct device_node *aux_bus;
> >> -    struct device *dev;
> >>         dp_priv = container_of(dp, struct dp_display_private,
> >> dp_display);
> >> -    dev = &dp_priv->pdev->dev;
> >> -    aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
> >> -
> >> -    if (aux_bus && dp->is_edp) {
> >> -        /*
> >> -         * The code below assumes that the panel will finish probing
> >> -         * by the time devm_of_dp_aux_populate_ep_devices() returns.
> >> -         * This isn't a great assumption since it will fail if the
> >> -         * panel driver is probed asynchronously but is the best we
> >> -         * can do without a bigger driver reorganization.
> >> -         */
> >> -        rc = of_dp_aux_populate_bus(dp_priv->aux, NULL);
> >> -        of_node_put(aux_bus);
> >> -        if (rc)
> >> -            goto error;
> >> -    } else if (dp->is_edp) {
> >> -        DRM_ERROR("eDP aux_bus not found\n");
> >> -        return -ENODEV;
> >> -    }
> >>         /*
> >>        * External bridges are mandatory for eDP interfaces: one has to
> >> @@ -1551,17 +1560,9 @@ static int dp_display_get_next_bridge(struct
> >> msm_dp *dp)
> >>       if (!dp->is_edp && rc == -ENODEV)
> >>           return 0;
> >>   -    if (!rc) {
> >> +    if (!rc)
> >>           dp->next_bridge = dp_priv->parser->next_bridge;
> >> -        return 0;
> >> -    }
> >>   -error:
> >> -    if (dp->is_edp) {
> >> -        of_dp_aux_depopulate_bus(dp_priv->aux);
> >> -        dp_display_host_phy_exit(dp_priv);
> >> -        dp_display_host_deinit(dp_priv);
> >> -    }
> >>       return rc;
> >>   }
> >
Kuogee Hsieh July 20, 2023, 8:27 p.m. UTC | #3
On 7/10/2023 11:24 AM, Dmitry Baryshkov wrote:
> [Restored CC list]
>
> On Mon, 10 Jul 2023 at 20:08, Kuogee Hsieh <quic_khsieh@quicinc.com> wrote:
>>
>> On 7/7/2023 5:32 PM, Dmitry Baryshkov wrote:
>>> On 08/07/2023 02:52, Kuogee Hsieh wrote:
>>>> Move of_dp_aux_populate_bus() to dp_display_probe() for eDP
>>>> from dp_display_bind() so that probe deferral cases can be
>>>> handled effectively
>>>>
>>>> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
>>>> ---
>>>>    drivers/gpu/drm/msm/dp/dp_aux.c     | 25 ++++++++++++
>>>>    drivers/gpu/drm/msm/dp/dp_display.c | 79
>>>> +++++++++++++++++++------------------
>>>>    2 files changed, 65 insertions(+), 39 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c
>>>> b/drivers/gpu/drm/msm/dp/dp_aux.c
>>>> index c592064..c1baffb 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
>>>> @@ -505,6 +505,21 @@ void dp_aux_unregister(struct drm_dp_aux *dp_aux)
>>>>        drm_dp_aux_unregister(dp_aux);
>>>>    }
>>>>    +static int dp_wait_hpd_asserted(struct drm_dp_aux *dp_aux,
>>>> +                 unsigned long wait_us)
>>>> +{
>>>> +    int ret;
>>>> +    struct dp_aux_private *aux;
>>>> +
>>>> +    aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
>>>> +
>>>> +    pm_runtime_get_sync(aux->dev);
>>>> +    ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog);
>>>> +    pm_runtime_put_sync(aux->dev);
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +
>>>>    struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog
>>>> *catalog,
>>>>                      bool is_edp)
>>>>    {
>>>> @@ -528,6 +543,16 @@ struct drm_dp_aux *dp_aux_get(struct device
>>>> *dev, struct dp_catalog *catalog,
>>>>        aux->catalog = catalog;
>>>>        aux->retry_cnt = 0;
>>>>    +    /*
>>>> +     * Use the drm_dp_aux_init() to use the aux adapter
>>>> +     * before registering aux with the DRM device.
>>>> +     */
>>>> +    aux->dp_aux.name = "dpu_dp_aux";
>>>> +    aux->dp_aux.dev = dev;
>>>> +    aux->dp_aux.transfer = dp_aux_transfer;
>>>> +    aux->dp_aux.wait_hpd_asserted = dp_wait_hpd_asserted;
>>>> +    drm_dp_aux_init(&aux->dp_aux);
>>>> +
>>>>        return &aux->dp_aux;
>>>>    }
>>>>    diff --git a/drivers/gpu/drm/msm/dp/dp_display.c
>>>> b/drivers/gpu/drm/msm/dp/dp_display.c
>>>> index 185f1eb..7ed4bea 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>>>> @@ -302,10 +302,6 @@ static int dp_display_bind(struct device *dev,
>>>> struct device *master,
>>>>            goto end;
>>>>        }
>>>>    -    pm_runtime_enable(dev);
>>>> -    pm_runtime_set_autosuspend_delay(dev, 1000);
>>>> -    pm_runtime_use_autosuspend(dev);
>>>> -
>>>>        return 0;
>>>>    end:
>>>>        return rc;
>>>> @@ -322,8 +318,6 @@ static void dp_display_unbind(struct device *dev,
>>>> struct device *master,
>>>>          kthread_stop(dp->ev_tsk);
>>>>    -    of_dp_aux_depopulate_bus(dp->aux);
>>>> -
>>>>        dp_power_client_deinit(dp->power);
>>>>        dp_unregister_audio_driver(dev, dp->audio);
>>>>        dp_aux_unregister(dp->aux);
>>>> @@ -1245,6 +1239,29 @@ static const struct msm_dp_desc
>>>> *dp_display_get_desc(struct platform_device *pde
>>>>        return NULL;
>>>>    }
>>>>    +static void of_dp_aux_depopulate_bus_void(void *data)
>>>> +{
>>>> +    of_dp_aux_depopulate_bus(data);
>>>> +}
>>>> +
>>>> +static int dp_display_auxbus_emulation(struct dp_display_private *dp)
>>> Why is it called emulation?
>>>
>>>> +{
>>>> +    struct device *dev = &dp->pdev->dev;
>>>> +    struct device_node *aux_bus;
>>>> +    int ret = 0;
>>>> +
>>>> +    aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
>>>> +
>>>> +    if (aux_bus) {
>>>> +        ret = devm_of_dp_aux_populate_bus(dp->aux, NULL);
>>> And here you missed the whole point of why we have been asking for.
>>> Please add a sensible `done_probing' callback, which will call
>>> component_add(). This way the DP component will only be registered
>>> when the panel has been probed. Keeping us from the component binding
>>> retries and corresponding side effects.
>>>
>>>> +
>>>> +        devm_add_action_or_reset(dev, of_dp_aux_depopulate_bus_void,
>>>> +                     dp->aux);
>>> Useless, it's already handled by the devm_ part of the
>>> devm_of_dp_aux_populate_bus().
>>>
>>>> +    }
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +
>>>>    static int dp_display_probe(struct platform_device *pdev)
>>>>    {
>>>>        int rc = 0;
>>>> @@ -1290,8 +1307,18 @@ static int dp_display_probe(struct
>>>> platform_device *pdev)
>>>>          platform_set_drvdata(pdev, &dp->dp_display);
>>>>    +    pm_runtime_enable(&pdev->dev);
>>>> +    pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
>>>> +    pm_runtime_use_autosuspend(&pdev->dev);
>>> Can we have this in probe right from the patch #2?
>> no, at patch#2, devm_of_dp_aux_populate_bus() is done ta bind timing.
>>
>> The device used by pm_runtime_get_sync() of generic_edp_panel_probe()
>> which is derived from devm_of_dp_aux_populate_bus() is different the
>> &pdev->dev here.
> Excuse me, I don't get your answer. In patch #2 you have added
> pm_runtime_enable() / etc to dp_display_bind().
> In this patch you are moving these calls to dp_display_probe(). I
> think that the latter is a better place for enabling runtime PM and as
> such I've asked you to squash this chunk into patch #2.
> Why isn't that going to work?
>
> If I'm not mistaken here, the panel's call to pm_runtime_get_sync()
> will wake up the panel and all the parent devices, including the DP.
> That's what I meant in my comment regarding PM calls in the patch #1.
> pm_runtime_get_sync() / resume() / etc. do not only increase the
> runtime PM count. They do other things to parent devices, linked
> devices, etc.

sorry for late response,

yes, pm_runtime_enable() at probe() is better and i did that original. 
but it is not work.

I found that,

1) at dp_display_bind(), dev is mdss

2) at probe() dev is dp

3) pm_runtime_enable(dp's dev) and generic_edp_panel_probe() --> 
pm_runtime_get_sync(mdss's dev)



>>>> +
>>>>        dp_display_request_irq(dp);
>>>>    +    if (dp->dp_display.is_edp) {
>>>> +        rc = dp_display_auxbus_emulation(dp);
>>>> +        if (rc)
>>>> +            DRM_ERROR("eDP aux-bus emulation failed, rc=%d\n", rc);
>>>> +    }
>>>> +
>>>>        rc = component_add(&pdev->dev, &dp_display_comp_ops);
>>>>        if (rc) {
>>>>            DRM_ERROR("component add failed, rc=%d\n", rc);
>>>> @@ -1306,11 +1333,14 @@ static int dp_display_remove(struct
>>>> platform_device *pdev)
>>>>        struct dp_display_private *dp =
>>>> dev_get_dp_display_private(&pdev->dev);
>>>>          component_del(&pdev->dev, &dp_display_comp_ops);
>>>> -    dp_display_deinit_sub_modules(dp);
>>>> -
>>>>        platform_set_drvdata(pdev, NULL);
>>>> +
>>>> +    pm_runtime_dont_use_autosuspend(&pdev->dev);
>>>> +    pm_runtime_disable(&pdev->dev);
>>>>        pm_runtime_put_sync_suspend(&pdev->dev);
>>>>    +    dp_display_deinit_sub_modules(dp);
>>>> +
>>>>        return 0;
>>>>    }
>>>>    @@ -1514,31 +1544,10 @@ void msm_dp_debugfs_init(struct msm_dp
>>>> *dp_display, struct drm_minor *minor)
>>>>      static int dp_display_get_next_bridge(struct msm_dp *dp)
>>>>    {
>>>> -    int rc;
>>>> +    int rc = 0;
>>>>        struct dp_display_private *dp_priv;
>>>> -    struct device_node *aux_bus;
>>>> -    struct device *dev;
>>>>          dp_priv = container_of(dp, struct dp_display_private,
>>>> dp_display);
>>>> -    dev = &dp_priv->pdev->dev;
>>>> -    aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
>>>> -
>>>> -    if (aux_bus && dp->is_edp) {
>>>> -        /*
>>>> -         * The code below assumes that the panel will finish probing
>>>> -         * by the time devm_of_dp_aux_populate_ep_devices() returns.
>>>> -         * This isn't a great assumption since it will fail if the
>>>> -         * panel driver is probed asynchronously but is the best we
>>>> -         * can do without a bigger driver reorganization.
>>>> -         */
>>>> -        rc = of_dp_aux_populate_bus(dp_priv->aux, NULL);
>>>> -        of_node_put(aux_bus);
>>>> -        if (rc)
>>>> -            goto error;
>>>> -    } else if (dp->is_edp) {
>>>> -        DRM_ERROR("eDP aux_bus not found\n");
>>>> -        return -ENODEV;
>>>> -    }
>>>>          /*
>>>>         * External bridges are mandatory for eDP interfaces: one has to
>>>> @@ -1551,17 +1560,9 @@ static int dp_display_get_next_bridge(struct
>>>> msm_dp *dp)
>>>>        if (!dp->is_edp && rc == -ENODEV)
>>>>            return 0;
>>>>    -    if (!rc) {
>>>> +    if (!rc)
>>>>            dp->next_bridge = dp_priv->parser->next_bridge;
>>>> -        return 0;
>>>> -    }
>>>>    -error:
>>>> -    if (dp->is_edp) {
>>>> -        of_dp_aux_depopulate_bus(dp_priv->aux);
>>>> -        dp_display_host_phy_exit(dp_priv);
>>>> -        dp_display_host_deinit(dp_priv);
>>>> -    }
>>>>        return rc;
>>>>    }
>
>
Dmitry Baryshkov July 20, 2023, 10:19 p.m. UTC | #4
On 20/07/2023 23:27, Kuogee Hsieh wrote:
> 
> On 7/10/2023 11:24 AM, Dmitry Baryshkov wrote:
>> [Restored CC list]
>>
>> On Mon, 10 Jul 2023 at 20:08, Kuogee Hsieh <quic_khsieh@quicinc.com> 
>> wrote:
>>>
>>> On 7/7/2023 5:32 PM, Dmitry Baryshkov wrote:
>>>> On 08/07/2023 02:52, Kuogee Hsieh wrote:
>>>>> Move of_dp_aux_populate_bus() to dp_display_probe() for eDP
>>>>> from dp_display_bind() so that probe deferral cases can be
>>>>> handled effectively
>>>>>
>>>>> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
>>>>> ---
>>>>>    drivers/gpu/drm/msm/dp/dp_aux.c     | 25 ++++++++++++
>>>>>    drivers/gpu/drm/msm/dp/dp_display.c | 79
>>>>> +++++++++++++++++++------------------
>>>>>    2 files changed, 65 insertions(+), 39 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c
>>>>> b/drivers/gpu/drm/msm/dp/dp_aux.c
>>>>> index c592064..c1baffb 100644
>>>>> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
>>>>> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
>>>>> @@ -505,6 +505,21 @@ void dp_aux_unregister(struct drm_dp_aux *dp_aux)
>>>>>        drm_dp_aux_unregister(dp_aux);
>>>>>    }
>>>>>    +static int dp_wait_hpd_asserted(struct drm_dp_aux *dp_aux,
>>>>> +                 unsigned long wait_us)
>>>>> +{
>>>>> +    int ret;
>>>>> +    struct dp_aux_private *aux;
>>>>> +
>>>>> +    aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
>>>>> +
>>>>> +    pm_runtime_get_sync(aux->dev);
>>>>> +    ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog);
>>>>> +    pm_runtime_put_sync(aux->dev);
>>>>> +
>>>>> +    return ret;
>>>>> +}
>>>>> +
>>>>>    struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog
>>>>> *catalog,
>>>>>                      bool is_edp)
>>>>>    {
>>>>> @@ -528,6 +543,16 @@ struct drm_dp_aux *dp_aux_get(struct device
>>>>> *dev, struct dp_catalog *catalog,
>>>>>        aux->catalog = catalog;
>>>>>        aux->retry_cnt = 0;
>>>>>    +    /*
>>>>> +     * Use the drm_dp_aux_init() to use the aux adapter
>>>>> +     * before registering aux with the DRM device.
>>>>> +     */
>>>>> +    aux->dp_aux.name = "dpu_dp_aux";
>>>>> +    aux->dp_aux.dev = dev;
>>>>> +    aux->dp_aux.transfer = dp_aux_transfer;
>>>>> +    aux->dp_aux.wait_hpd_asserted = dp_wait_hpd_asserted;
>>>>> +    drm_dp_aux_init(&aux->dp_aux);
>>>>> +
>>>>>        return &aux->dp_aux;
>>>>>    }
>>>>>    diff --git a/drivers/gpu/drm/msm/dp/dp_display.c
>>>>> b/drivers/gpu/drm/msm/dp/dp_display.c
>>>>> index 185f1eb..7ed4bea 100644
>>>>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>>>>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>>>>> @@ -302,10 +302,6 @@ static int dp_display_bind(struct device *dev,
>>>>> struct device *master,
>>>>>            goto end;
>>>>>        }
>>>>>    -    pm_runtime_enable(dev);
>>>>> -    pm_runtime_set_autosuspend_delay(dev, 1000);
>>>>> -    pm_runtime_use_autosuspend(dev);
>>>>> -
>>>>>        return 0;
>>>>>    end:
>>>>>        return rc;
>>>>> @@ -322,8 +318,6 @@ static void dp_display_unbind(struct device *dev,
>>>>> struct device *master,
>>>>>          kthread_stop(dp->ev_tsk);
>>>>>    -    of_dp_aux_depopulate_bus(dp->aux);
>>>>> -
>>>>>        dp_power_client_deinit(dp->power);
>>>>>        dp_unregister_audio_driver(dev, dp->audio);
>>>>>        dp_aux_unregister(dp->aux);
>>>>> @@ -1245,6 +1239,29 @@ static const struct msm_dp_desc
>>>>> *dp_display_get_desc(struct platform_device *pde
>>>>>        return NULL;
>>>>>    }
>>>>>    +static void of_dp_aux_depopulate_bus_void(void *data)
>>>>> +{
>>>>> +    of_dp_aux_depopulate_bus(data);
>>>>> +}
>>>>> +
>>>>> +static int dp_display_auxbus_emulation(struct dp_display_private *dp)
>>>> Why is it called emulation?
>>>>
>>>>> +{
>>>>> +    struct device *dev = &dp->pdev->dev;
>>>>> +    struct device_node *aux_bus;
>>>>> +    int ret = 0;
>>>>> +
>>>>> +    aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
>>>>> +
>>>>> +    if (aux_bus) {
>>>>> +        ret = devm_of_dp_aux_populate_bus(dp->aux, NULL);
>>>> And here you missed the whole point of why we have been asking for.
>>>> Please add a sensible `done_probing' callback, which will call
>>>> component_add(). This way the DP component will only be registered
>>>> when the panel has been probed. Keeping us from the component binding
>>>> retries and corresponding side effects.
>>>>
>>>>> +
>>>>> +        devm_add_action_or_reset(dev, of_dp_aux_depopulate_bus_void,
>>>>> +                     dp->aux);
>>>> Useless, it's already handled by the devm_ part of the
>>>> devm_of_dp_aux_populate_bus().
>>>>
>>>>> +    }
>>>>> +
>>>>> +    return ret;
>>>>> +}
>>>>> +
>>>>>    static int dp_display_probe(struct platform_device *pdev)
>>>>>    {
>>>>>        int rc = 0;
>>>>> @@ -1290,8 +1307,18 @@ static int dp_display_probe(struct
>>>>> platform_device *pdev)
>>>>>          platform_set_drvdata(pdev, &dp->dp_display);
>>>>>    +    pm_runtime_enable(&pdev->dev);
>>>>> +    pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
>>>>> +    pm_runtime_use_autosuspend(&pdev->dev);
>>>> Can we have this in probe right from the patch #2?
>>> no, at patch#2, devm_of_dp_aux_populate_bus() is done ta bind timing.
>>>
>>> The device used by pm_runtime_get_sync() of generic_edp_panel_probe()
>>> which is derived from devm_of_dp_aux_populate_bus() is different the
>>> &pdev->dev here.
>> Excuse me, I don't get your answer. In patch #2 you have added
>> pm_runtime_enable() / etc to dp_display_bind().
>> In this patch you are moving these calls to dp_display_probe(). I
>> think that the latter is a better place for enabling runtime PM and as
>> such I've asked you to squash this chunk into patch #2.
>> Why isn't that going to work?
>>
>> If I'm not mistaken here, the panel's call to pm_runtime_get_sync()
>> will wake up the panel and all the parent devices, including the DP.
>> That's what I meant in my comment regarding PM calls in the patch #1.
>> pm_runtime_get_sync() / resume() / etc. do not only increase the
>> runtime PM count. They do other things to parent devices, linked
>> devices, etc.
> 
> sorry for late response,
> 
> yes, pm_runtime_enable() at probe() is better and i did that original. 
> but it is not work.
> 
> I found that,
> 
> 1) at dp_display_bind(), dev is mdss

If the 'dev' is the issue, you can always use dp_display_private::pdev.

> 
> 2) at probe() dev is dp
> 
> 3) pm_runtime_enable(dp's dev) and generic_edp_panel_probe() --> 
> pm_runtime_get_sync(mdss's dev)

I might be missing something. Please describe, what exactly doesn't work.

> 
> 
> 
>>>>> +
>>>>>        dp_display_request_irq(dp);
>>>>>    +    if (dp->dp_display.is_edp) {
>>>>> +        rc = dp_display_auxbus_emulation(dp);
>>>>> +        if (rc)
>>>>> +            DRM_ERROR("eDP aux-bus emulation failed, rc=%d\n", rc);
>>>>> +    }
>>>>> +
>>>>>        rc = component_add(&pdev->dev, &dp_display_comp_ops);
>>>>>        if (rc) {
>>>>>            DRM_ERROR("component add failed, rc=%d\n", rc);
>>>>> @@ -1306,11 +1333,14 @@ static int dp_display_remove(struct
>>>>> platform_device *pdev)
>>>>>        struct dp_display_private *dp =
>>>>> dev_get_dp_display_private(&pdev->dev);
>>>>>          component_del(&pdev->dev, &dp_display_comp_ops);
>>>>> -    dp_display_deinit_sub_modules(dp);
>>>>> -
>>>>>        platform_set_drvdata(pdev, NULL);
>>>>> +
>>>>> +    pm_runtime_dont_use_autosuspend(&pdev->dev);
>>>>> +    pm_runtime_disable(&pdev->dev);
>>>>>        pm_runtime_put_sync_suspend(&pdev->dev);
>>>>>    +    dp_display_deinit_sub_modules(dp);
>>>>> +
>>>>>        return 0;
>>>>>    }
>>>>>    @@ -1514,31 +1544,10 @@ void msm_dp_debugfs_init(struct msm_dp
>>>>> *dp_display, struct drm_minor *minor)
>>>>>      static int dp_display_get_next_bridge(struct msm_dp *dp)
>>>>>    {
>>>>> -    int rc;
>>>>> +    int rc = 0;
>>>>>        struct dp_display_private *dp_priv;
>>>>> -    struct device_node *aux_bus;
>>>>> -    struct device *dev;
>>>>>          dp_priv = container_of(dp, struct dp_display_private,
>>>>> dp_display);
>>>>> -    dev = &dp_priv->pdev->dev;
>>>>> -    aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
>>>>> -
>>>>> -    if (aux_bus && dp->is_edp) {
>>>>> -        /*
>>>>> -         * The code below assumes that the panel will finish probing
>>>>> -         * by the time devm_of_dp_aux_populate_ep_devices() returns.
>>>>> -         * This isn't a great assumption since it will fail if the
>>>>> -         * panel driver is probed asynchronously but is the best we
>>>>> -         * can do without a bigger driver reorganization.
>>>>> -         */
>>>>> -        rc = of_dp_aux_populate_bus(dp_priv->aux, NULL);
>>>>> -        of_node_put(aux_bus);
>>>>> -        if (rc)
>>>>> -            goto error;
>>>>> -    } else if (dp->is_edp) {
>>>>> -        DRM_ERROR("eDP aux_bus not found\n");
>>>>> -        return -ENODEV;
>>>>> -    }
>>>>>          /*
>>>>>         * External bridges are mandatory for eDP interfaces: one 
>>>>> has to
>>>>> @@ -1551,17 +1560,9 @@ static int dp_display_get_next_bridge(struct
>>>>> msm_dp *dp)
>>>>>        if (!dp->is_edp && rc == -ENODEV)
>>>>>            return 0;
>>>>>    -    if (!rc) {
>>>>> +    if (!rc)
>>>>>            dp->next_bridge = dp_priv->parser->next_bridge;
>>>>> -        return 0;
>>>>> -    }
>>>>>    -error:
>>>>> -    if (dp->is_edp) {
>>>>> -        of_dp_aux_depopulate_bus(dp_priv->aux);
>>>>> -        dp_display_host_phy_exit(dp_priv);
>>>>> -        dp_display_host_deinit(dp_priv);
>>>>> -    }
>>>>>        return rc;
>>>>>    }
>>
>>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
index c592064..c1baffb 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.c
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -505,6 +505,21 @@  void dp_aux_unregister(struct drm_dp_aux *dp_aux)
 	drm_dp_aux_unregister(dp_aux);
 }
 
+static int dp_wait_hpd_asserted(struct drm_dp_aux *dp_aux,
+				 unsigned long wait_us)
+{
+	int ret;
+	struct dp_aux_private *aux;
+
+	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
+
+	pm_runtime_get_sync(aux->dev);
+	ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog);
+	pm_runtime_put_sync(aux->dev);
+
+	return ret;
+}
+
 struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
 			      bool is_edp)
 {
@@ -528,6 +543,16 @@  struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
 	aux->catalog = catalog;
 	aux->retry_cnt = 0;
 
+	/*
+	 * Use the drm_dp_aux_init() to use the aux adapter
+	 * before registering aux with the DRM device.
+	 */
+	aux->dp_aux.name = "dpu_dp_aux";
+	aux->dp_aux.dev = dev;
+	aux->dp_aux.transfer = dp_aux_transfer;
+	aux->dp_aux.wait_hpd_asserted = dp_wait_hpd_asserted;
+	drm_dp_aux_init(&aux->dp_aux);
+
 	return &aux->dp_aux;
 }
 
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 185f1eb..7ed4bea 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -302,10 +302,6 @@  static int dp_display_bind(struct device *dev, struct device *master,
 		goto end;
 	}
 
-	pm_runtime_enable(dev);
-	pm_runtime_set_autosuspend_delay(dev, 1000);
-	pm_runtime_use_autosuspend(dev);
-
 	return 0;
 end:
 	return rc;
@@ -322,8 +318,6 @@  static void dp_display_unbind(struct device *dev, struct device *master,
 
 	kthread_stop(dp->ev_tsk);
 
-	of_dp_aux_depopulate_bus(dp->aux);
-
 	dp_power_client_deinit(dp->power);
 	dp_unregister_audio_driver(dev, dp->audio);
 	dp_aux_unregister(dp->aux);
@@ -1245,6 +1239,29 @@  static const struct msm_dp_desc *dp_display_get_desc(struct platform_device *pde
 	return NULL;
 }
 
+static void of_dp_aux_depopulate_bus_void(void *data)
+{
+	of_dp_aux_depopulate_bus(data);
+}
+
+static int dp_display_auxbus_emulation(struct dp_display_private *dp)
+{
+	struct device *dev = &dp->pdev->dev;
+	struct device_node *aux_bus;
+	int ret = 0;
+
+	aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
+
+	if (aux_bus) {
+		ret = devm_of_dp_aux_populate_bus(dp->aux, NULL);
+
+		devm_add_action_or_reset(dev, of_dp_aux_depopulate_bus_void,
+					 dp->aux);
+	}
+
+	return ret;
+}
+
 static int dp_display_probe(struct platform_device *pdev)
 {
 	int rc = 0;
@@ -1290,8 +1307,18 @@  static int dp_display_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, &dp->dp_display);
 
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
+	pm_runtime_use_autosuspend(&pdev->dev);
+
 	dp_display_request_irq(dp);
 
+	if (dp->dp_display.is_edp) {
+		rc = dp_display_auxbus_emulation(dp);
+		if (rc)
+			DRM_ERROR("eDP aux-bus emulation failed, rc=%d\n", rc);
+	}
+
 	rc = component_add(&pdev->dev, &dp_display_comp_ops);
 	if (rc) {
 		DRM_ERROR("component add failed, rc=%d\n", rc);
@@ -1306,11 +1333,14 @@  static int dp_display_remove(struct platform_device *pdev)
 	struct dp_display_private *dp = dev_get_dp_display_private(&pdev->dev);
 
 	component_del(&pdev->dev, &dp_display_comp_ops);
-	dp_display_deinit_sub_modules(dp);
-
 	platform_set_drvdata(pdev, NULL);
+
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_sync_suspend(&pdev->dev);
 
+	dp_display_deinit_sub_modules(dp);
+
 	return 0;
 }
 
@@ -1514,31 +1544,10 @@  void msm_dp_debugfs_init(struct msm_dp *dp_display, struct drm_minor *minor)
 
 static int dp_display_get_next_bridge(struct msm_dp *dp)
 {
-	int rc;
+	int rc = 0;
 	struct dp_display_private *dp_priv;
-	struct device_node *aux_bus;
-	struct device *dev;
 
 	dp_priv = container_of(dp, struct dp_display_private, dp_display);
-	dev = &dp_priv->pdev->dev;
-	aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
-
-	if (aux_bus && dp->is_edp) {
-		/*
-		 * The code below assumes that the panel will finish probing
-		 * by the time devm_of_dp_aux_populate_ep_devices() returns.
-		 * This isn't a great assumption since it will fail if the
-		 * panel driver is probed asynchronously but is the best we
-		 * can do without a bigger driver reorganization.
-		 */
-		rc = of_dp_aux_populate_bus(dp_priv->aux, NULL);
-		of_node_put(aux_bus);
-		if (rc)
-			goto error;
-	} else if (dp->is_edp) {
-		DRM_ERROR("eDP aux_bus not found\n");
-		return -ENODEV;
-	}
 
 	/*
 	 * External bridges are mandatory for eDP interfaces: one has to
@@ -1551,17 +1560,9 @@  static int dp_display_get_next_bridge(struct msm_dp *dp)
 	if (!dp->is_edp && rc == -ENODEV)
 		return 0;
 
-	if (!rc) {
+	if (!rc)
 		dp->next_bridge = dp_priv->parser->next_bridge;
-		return 0;
-	}
 
-error:
-	if (dp->is_edp) {
-		of_dp_aux_depopulate_bus(dp_priv->aux);
-		dp_display_host_phy_exit(dp_priv);
-		dp_display_host_deinit(dp_priv);
-	}
 	return rc;
 }