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Message-ID: <f2fbcf6e-65cf-c078-e11f-1ca74960a71e@quicinc.com>
Date:   Tue, 3 Oct 2023 13:18:22 -0700
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Subject: Re: [PATCH v4 8/8] drm/msm/dp: move of_dp_aux_populate_bus() to eDP
 probe()
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To:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
CC:     <dri-devel@lists.freedesktop.org>, <robdclark@gmail.com>,
        <sean@poorly.run>, <swboyd@chromium.org>, <dianders@chromium.org>,
        <vkoul@kernel.org>, <daniel@ffwll.ch>, <airlied@gmail.com>,
        <agross@kernel.org>, <andersson@kernel.org>,
        <quic_abhinavk@quicinc.com>, <quic_jesszhan@quicinc.com>,
        <quic_sbillaka@quicinc.com>, <marijn.suijten@somainline.org>,
        <freedreno@lists.freedesktop.org>, <linux-arm-msm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <1695848028-18023-1-git-send-email-quic_khsieh@quicinc.com>
 <1695848028-18023-9-git-send-email-quic_khsieh@quicinc.com>
 <CAA8EJprfjt7w+3YJAieBabuMso=-obRXss7-9Jrif23WmOJw5w@mail.gmail.com>
 <2d8d4354-6dbb-e810-6efb-ca6b31f71b45@quicinc.com>
 <e7576c3b-82d2-4902-a19c-af2878ef7dbd@linaro.org>
From:   Kuogee Hsieh <quic_khsieh@quicinc.com>
In-Reply-To: <e7576c3b-82d2-4902-a19c-af2878ef7dbd@linaro.org>
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On 10/3/2023 10:56 AM, Dmitry Baryshkov wrote:
> On 03/10/2023 20:25, Kuogee Hsieh wrote:
>>
>> On 9/27/2023 2:57 PM, Dmitry Baryshkov wrote:
>>> On Wed, 27 Sept 2023 at 23:54, Kuogee Hsieh 
>>> <quic_khsieh@quicinc.com> wrote:
>>>> Currently eDP population is done at msm_dp_modeset_init() which happen
>>>> at binding time. Move eDP population to be done at display probe time
>>>> so that probe deferral cases can be handled effectively.
>>>> wait_for_hpd_asserted callback is added during drm_dp_aux_init()
>>>> to ensure eDP's HPD is up before proceeding eDP population.
>>>>
>>>> Changes in v4:
>>>> -- delete duplicate initialize code to dp_aux before 
>>>> drm_dp_aux_register()
>>>> -- delete of_get_child_by_name(dev->of_node, "aux-bus") and inline 
>>>> the function
>>>> -- not initialize rc = 0
>>>>
>>>> Changes in v3:
>>>> -- add done_probing callback into devm_of_dp_aux_populate_bus()
>>>>
>>>> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
>>>> ---
>>>>   drivers/gpu/drm/msm/dp/dp_aux.c     | 34 ++++++++++++++----
>>>>   drivers/gpu/drm/msm/dp/dp_display.c | 69 
>>>> ++++++++++++++++++-------------------
>>>>   2 files changed, 60 insertions(+), 43 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c 
>>>> b/drivers/gpu/drm/msm/dp/dp_aux.c
>>>> index 22eb774..425b5c5 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
>>>> @@ -480,7 +480,6 @@ void dp_aux_deinit(struct drm_dp_aux *dp_aux)
>>>>
>>>>   int dp_aux_register(struct drm_dp_aux *dp_aux)
>>>>   {
>>>> -       struct dp_aux_private *aux;
>>>>          int ret;
>>>>
>>>>          if (!dp_aux) {
>>>> @@ -488,12 +487,7 @@ int dp_aux_register(struct drm_dp_aux *dp_aux)
>>>>                  return -EINVAL;
>>>>          }
>>>>
>>>> -       aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
>>>> -
>>>> -       aux->dp_aux.name = "dpu_dp_aux";
>>>> -       aux->dp_aux.dev = aux->dev;
>>>> -       aux->dp_aux.transfer = dp_aux_transfer;
>>>> -       ret = drm_dp_aux_register(&aux->dp_aux);
>>>> +       ret = drm_dp_aux_register(dp_aux);
>>>>          if (ret) {
>>>>                  DRM_ERROR("%s: failed to register drm aux: %d\n", 
>>>> __func__,
>>>>                                  ret);
>>>> @@ -508,6 +502,21 @@ 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);
>>> Ok, so here you have used put_sync instead of autosuspend. Can we have
>>> some uniformity? (I'd prefer to see put_sync or just put everywhere)
>>
>>
>> my point is,
>>
>> since display is user interface,
>>
>> if there has any inputs before timer expire then there is no reason 
>> to execute  pm_runtime_suspend().
>>
>> otherwise pm_runtime_suspend() should be executed.
>>
>> Therefore I used autosuspend  at aux_transfer() an 
>> ddp_bridge_atomic_post_disable().
>>
>> here is not related to user interface so that i use put_sysn() directly.
>>
>> is my point make sense?
>>
>>   or should I drop all autosuspend and replace them with put_sync()?
>
> This was my question from the beginning: what was the reason for using 
> autosuspend? Did it bring any sensible improvement in the disable & 
> reenable path?

ok, i got your point.

1) I will use put_sync() at dp_bridge_atomic_dsiable() and 
dp_bridge_hpd_disable() instead of put_autosuspend().

2) keep pm_runtime_put_autosuspend() at dp_aux_transfer().

Is this good?

>
>>
>>
>>>
>>>> +
>>>> +       return ret;
>>>> +}
>>>> +
>>>>   struct drm_dp_aux *dp_aux_get(struct device *dev, struct 
>>>> dp_catalog *catalog,
>>>>                                bool is_edp)
>>>>   {
>>>> @@ -531,6 +540,17 @@ 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 so that
>>>> +        * msm edp panel can be detected by generic_dep_panel_probe().
>>> eDP, AUX, generic_edp_panel_probe().
>>>
>>>> +        */
>>>> +       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 711d262..9a2b403 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>>>> @@ -1203,6 +1203,28 @@ static const struct msm_dp_desc 
>>>> *dp_display_get_desc(struct platform_device *pde
>>>>          return NULL;
>>>>   }
>>>>
>>>> +static int dp_auxbus_done_probe(struct drm_dp_aux *aux)
>>>> +{
>>>> +       int rc;
>>>> +
>>>> +       rc = component_add(aux->dev, &dp_display_comp_ops);
>>>> +       if (rc)
>>>> +               DRM_ERROR("eDP component add failed, rc=%d\n", rc);
>>> drop.
>>>
>>>> +
>>>> +       return rc;
>>>> +}
>>>> +
>>>> +static inline int dp_display_auxbus_population(struct 
>>>> dp_display_private *dp)
>>> It's not `population`. It is just `populate`.
>>>
>>> Also please inline this function.
>>>
>>>
>>>> +{
>>>> +       int ret;
>>>> +
>>>> +       ret = devm_of_dp_aux_populate_bus(dp->aux, 
>>>> dp_auxbus_done_probe);
>>>> +       if (ret == -ENODEV)
>>>> +               DRM_ERROR("aux-bus not found\n");
>>>> +
>>>> +       return ret;
>>>> +}
>>>> +
>>>>   static int dp_display_probe(struct platform_device *pdev)
>>>>   {
>>>>          int rc = 0;
>>>> @@ -1271,10 +1293,16 @@ static int dp_display_probe(struct 
>>>> platform_device *pdev)
>>>>          if (rc)
>>>>                  return rc;
>>>>
>>>> -       rc = component_add(&pdev->dev, &dp_display_comp_ops);
>>>> -       if (rc) {
>>>> -               DRM_ERROR("component add failed, rc=%d\n", rc);
>>>> -               dp_display_deinit_sub_modules(dp);
>>>> +       if (dp->dp_display.is_edp) {
>>>> +               rc = dp_display_auxbus_population(dp);
>>>> +               if (rc)
>>>> +                       DRM_ERROR("eDP auxbus population failed, 
>>>> rc=%d\n", rc);
>>>> +       } else {
>>>> +               rc = component_add(&pdev->dev, &dp_display_comp_ops);
>>>> +               if (rc) {
>>>> +                       DRM_ERROR("component add failed, rc=%d\n", 
>>>> rc);
>>>> +                       dp_display_deinit_sub_modules(dp);
>>>> +               }
>>>>          }
>>>>
>>>>          return rc;
>>>> @@ -1285,8 +1313,6 @@ 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);
>>>>
>>>>          dp_display_deinit_sub_modules(dp);
>>>> @@ -1385,29 +1411,8 @@ static int dp_display_get_next_bridge(struct 
>>>> msm_dp *dp)
>>>>   {
>>>>          int rc;
>>>>          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
>>>> @@ -1420,17 +1425,9 @@ 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;
>>>>   }
>>>>
>>>> -- 
>>>> 2.7.4
>>>>
>>>
>