Re: [PATCH v4 8/8] drm/msm/dp: move of_dp_aux_populate_bus() to eDP probe()

From: Kuogee Hsieh
Date: Tue Oct 03 2023 - 16:18:43 EST



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@xxxxxxxxxxx> 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@xxxxxxxxxxx>
---
  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