Message-ID: <CAA8EJpptTDQVO189OcXqJw+VN+1EkgaQd6TJwcGpGxdYTR1vhQ@mail.gmail.com>
Date:   Thu, 28 Sep 2023 00:41:46 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Kuogee Hsieh <quic_khsieh@...cinc.com>
Cc:     dri-devel@...ts.freedesktop.org, robdclark@...il.com,
        sean@...rly.run, swboyd@...omium.org, dianders@...omium.org,
        vkoul@...nel.org, daniel@...ll.ch, airlied@...il.com,
        agross@...nel.org, andersson@...nel.org, quic_abhinavk@...cinc.com,
        quic_jesszhan@...cinc.com, quic_sbillaka@...cinc.com,
        marijn.suijten@...ainline.org, freedreno@...ts.freedesktop.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 5/8] drm/msm/dp: incorporate pm_runtime framework into
 DP driver

On Wed, 27 Sept 2023 at 23:54, Kuogee Hsieh <quic_khsieh@...cinc.com> wrote:
>
> Currently DP driver is executed independent of PM runtime framework.
> This lead to msm edp panel can not be detected by edp_panel driver at
> generic_edp_panel_probe() due to aux dpcd read failed at msm edp driver.

eDP, AUX, DPCD. leads. not being detected, s/at/during.

Also there is no msm eDP driver.

> Incorporating pm runtime framework into DP driver so that both power and

Incorporate. PM

> clocks to enable/disable host controller fits with PM runtime mechanism.

Ugh?

> Once pm runtime framework is incorporated into DP driver, wake up device

waking

> from power up path is not necessary. Hence remove it.
> Since DP is part of user interface, we choice to use autosuspend feature
> with timer of one second. pm runtime suspends is prevented from happening
> until timer expired.

No, this is not the right reason to use autosuspend. Please use normal
suspend unless there is a performance regression caused by the
suspend/resume paths.

>
> Changes in v4:
> -- reworded commit text to explain why pm_framework is required for edp panel
> -- reworded commit text to explain autosuspend is choiced
> -- delete EV_POWER_PM_GET and PM_EV_POWER_PUT from changes #3
> -- delete dp_display_pm_get() and dp_display_pm_Put() from changes #3
> -- return value from pm_runtime_resume_and_get() directly
> -- check return value of devm_pm_runtime_enable()
> -- delete pm_runtime_xxx from dp_display_remove()
> -- drop dp_display_host_init() from EV_HPD_INIT_SETUP
>
> Changes in v3:
> -- incorporate removing pm_runtime_xx() from dp_pwer.c to this patch
> -- use pm_runtime_resume_and_get() instead of pm_runtime_get()
> -- error checking pm_runtime_resume_and_get() return value
> -- add EV_POWER_PM_GET and PM_EV_POWER_PUT to handle HPD_GPIO case
>
> Signed-off-by: Kuogee Hsieh <quic_khsieh@...cinc.com>
> Reported-by: kernel test robot <lkp@...el.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_aux.c     |  6 +++
>  drivers/gpu/drm/msm/dp/dp_display.c | 95 +++++++++++++++++++++++++++----------
>  drivers/gpu/drm/msm/dp/dp_power.c   | 16 -------
>  drivers/gpu/drm/msm/dp/dp_power.h   | 11 -----
>  4 files changed, 77 insertions(+), 51 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
> index 8e3b677..22eb774 100644
> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
> @@ -291,6 +291,10 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
>                 return -EINVAL;
>         }
>
> +       ret = pm_runtime_resume_and_get(dp_aux->dev);
> +       if (ret)
> +               return  ret;
> +
>         mutex_lock(&aux->mutex);
>         if (!aux->initted) {
>                 ret = -EIO;
> @@ -364,6 +368,8 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
>
>  exit:
>         mutex_unlock(&aux->mutex);
> +       pm_runtime_mark_last_busy(dp_aux->dev);
> +       pm_runtime_put_autosuspend(dp_aux->dev);
>
>         return ret;
>  }
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index 3ef141c..bfb4692 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -276,8 +276,6 @@ static int dp_display_bind(struct device *dev, struct device *master,
>         dp->dp_display.drm_dev = drm;
>         priv->dp[dp->id] = &dp->dp_display;
>
> -
> -

Is this also a part of pm_runtime support? No, it is not.

>         dp->drm_dev = drm;
>         dp->aux->drm_dev = drm;
>         rc = dp_aux_register(dp->aux);
> @@ -286,7 +284,6 @@ static int dp_display_bind(struct device *dev, struct device *master,
>                 goto end;
>         }
>
> -

And this. If you want to clean up stray empty lines, please split that
to a separate patch.

>         rc = dp_register_audio_driver(dev, dp->audio);
>         if (rc) {
>                 DRM_ERROR("Audio registration Dp failed\n");
> @@ -310,15 +307,10 @@ static void dp_display_unbind(struct device *dev, struct device *master,
>         struct dp_display_private *dp = dev_get_dp_display_private(dev);
>         struct msm_drm_private *priv = dev_get_drvdata(master);
>
> -       /* disable all HPD interrupts */
> -       if (dp->core_initialized)
> -               dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_INT_MASK, false);
> -
>         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);
>         dp->drm_dev = NULL;
> @@ -460,6 +452,16 @@ static void dp_display_host_deinit(struct dp_display_private *dp)
>  static int dp_display_usbpd_configure_cb(struct device *dev)
>  {
>         struct dp_display_private *dp = dev_get_dp_display_private(dev);
> +       int ret;
> +
> +       if (!dp->dp_display.internal_hpd) {

I'd say, drop the condition here.

> +               /* hpd through gpio */

Why? !internal_hpd means any possible way of delivering an HPD event.
For example, via the USB-C TCPM.

> +               ret = pm_runtime_resume_and_get(&dp->pdev->dev);

Which function contains corresponding pm_runtime_put()?

> +               if (ret) {
> +                       DRM_ERROR("failed to start power\n");

failed to resume

> +                       return ret;
> +               }
> +       }
>
>         dp_display_host_phy_init(dp);
>
> @@ -1086,7 +1088,6 @@ static int hpd_event_thread(void *data)
>
>                 switch (todo->event_id) {
>                 case EV_HPD_INIT_SETUP:
> -                       dp_display_host_init(dp_priv);
>                         break;
>                 case EV_HPD_PLUG_INT:
>                         dp_hpd_plug_handle(dp_priv, todo->data);
> @@ -1263,6 +1264,13 @@ static int dp_display_probe(struct platform_device *pdev)
>
>         platform_set_drvdata(pdev, &dp->dp_display);
>
> +       rc = devm_pm_runtime_enable(&pdev->dev);
> +       if (rc)
> +               return rc;

Missing submodules deinit.

> +
> +       pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
> +       pm_runtime_use_autosuspend(&pdev->dev);
> +
>         rc = dp_display_request_irq(dp);
>         if (rc)
>                 return rc;
> @@ -1285,6 +1293,34 @@ static int dp_display_remove(struct platform_device *pdev)
>
>         platform_set_drvdata(pdev, NULL);
>
> +       dp_display_deinit_sub_modules(dp);

There is already a call to dp_display_deinit_sub_modules() in
dp_display_remove().
> +
> +       return 0;
> +}
> +
> +static int dp_pm_runtime_suspend(struct device *dev)
> +{
> +       struct dp_display_private *dp = dev_get_dp_display_private(dev);
> +
> +       if (dp->dp_display.is_edp) {
> +               dp_display_host_phy_exit(dp);
> +               dp_catalog_ctrl_hpd_disable(dp->catalog);
> +       }

I don't see where this code was removed.

> +       dp_display_host_deinit(dp);
> +
> +       return 0;
> +}
> +
> +static int dp_pm_runtime_resume(struct device *dev)
> +{
> +       struct dp_display_private *dp = dev_get_dp_display_private(dev);
> +
> +       dp_display_host_init(dp);
> +       if (dp->dp_display.is_edp) {
> +               dp_catalog_ctrl_hpd_enable(dp->catalog);
> +               dp_display_host_phy_init(dp);
> +       }
> +
>         return 0;
>  }
>
> @@ -1389,6 +1425,7 @@ static int dp_pm_suspend(struct device *dev)
>  }
>
>  static const struct dev_pm_ops dp_pm_ops = {
> +       SET_RUNTIME_PM_OPS(dp_pm_runtime_suspend, dp_pm_runtime_resume, NULL)
>         .suspend = dp_pm_suspend,
>         .resume =  dp_pm_resume,
>  };
> @@ -1473,10 +1510,6 @@ static int dp_display_get_next_bridge(struct msm_dp *dp)
>         aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
>
>         if (aux_bus && dp->is_edp) {
> -               dp_display_host_init(dp_priv);
> -               dp_catalog_ctrl_hpd_enable(dp_priv->catalog);
> -               dp_display_host_phy_init(dp_priv);
> -
>                 /*
>                  * The code below assumes that the panel will finish probing
>                  * by the time devm_of_dp_aux_populate_ep_devices() returns.
> @@ -1578,6 +1611,11 @@ void dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
>                 dp_hpd_plug_handle(dp_display, 0);
>
>         mutex_lock(&dp_display->event_mutex);
> +       if (pm_runtime_resume_and_get(&dp_display->pdev->dev)) {
> +               DRM_ERROR("failed to start power\n");

failed to resume.

> +               mutex_unlock(&dp_display->event_mutex);
> +               return;
> +       }
>
>         state = dp_display->hpd_state;
>         if (state != ST_DISPLAY_OFF && state != ST_MAINLINK_READY) {
> @@ -1642,10 +1680,9 @@ void dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
>         mutex_lock(&dp_display->event_mutex);
>
>         state = dp_display->hpd_state;
> -       if (state != ST_DISCONNECT_PENDING && state != ST_CONNECTED) {
> -               mutex_unlock(&dp_display->event_mutex);
> -               return;
> -       }
> +       if (state != ST_DISCONNECT_PENDING && state != ST_CONNECTED)
> +               drm_dbg_dp(dp->drm_dev, "type=%d wrong hpd_state=%d\n",
> +                          dp->connector_type, state);
>
>         dp_display_disable(dp_display);
>
> @@ -1658,6 +1695,9 @@ void dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
>         }
>
>         drm_dbg_dp(dp->drm_dev, "type=%d Done\n", dp->connector_type);
> +
> +       pm_runtime_mark_last_busy(&dp_display->pdev->dev);
> +       pm_runtime_put_autosuspend(&dp_display->pdev->dev);
>         mutex_unlock(&dp_display->event_mutex);
>  }
>
> @@ -1697,6 +1737,12 @@ void dp_bridge_hpd_enable(struct drm_bridge *bridge)
>         struct dp_display_private *dp = container_of(dp_display, struct dp_display_private, dp_display);
>
>         mutex_lock(&dp->event_mutex);
> +       if (pm_runtime_resume_and_get(&dp->pdev->dev)) {
> +               DRM_ERROR("failed to start power\n");
> +               mutex_unlock(&dp->event_mutex);
> +               return;
> +       }
> +
>         dp_catalog_ctrl_hpd_enable(dp->catalog);
>
>         /* enable HDP interrupts */
> @@ -1718,6 +1764,9 @@ void dp_bridge_hpd_disable(struct drm_bridge *bridge)
>         dp_catalog_ctrl_hpd_disable(dp->catalog);
>
>         dp_display->internal_hpd = false;
> +
> +       pm_runtime_mark_last_busy(&dp->pdev->dev);
> +       pm_runtime_put_autosuspend(&dp->pdev->dev);
>         mutex_unlock(&dp->event_mutex);
>  }
>
> @@ -1732,13 +1781,11 @@ void dp_bridge_hpd_notify(struct drm_bridge *bridge,
>         if (dp_display->internal_hpd)
>                 return;
>
> -       if (!dp->core_initialized) {
> -               drm_dbg_dp(dp->drm_dev, "not initialized\n");
> -               return;
> -       }
> -
> -       if (!dp_display->link_ready && status == connector_status_connected)
> +       /* hpd through gpio */

Lack of the comment might be better than the incorrect comment.

> +       if (!dp_display->link_ready && status == connector_status_connected) {
> +               dp->hpd_state = ST_DISCONNECTED;

Is this also a part of pm_runtime support?

>                 dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0);
> -       else if (dp_display->link_ready && status == connector_status_disconnected)
> +       } else if (dp_display->link_ready && status == connector_status_disconnected) {
>                 dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
> +       }
>  }
> diff --git a/drivers/gpu/drm/msm/dp/dp_power.c b/drivers/gpu/drm/msm/dp/dp_power.c
> index 5cb84ca..863c766 100644
> --- a/drivers/gpu/drm/msm/dp/dp_power.c
> +++ b/drivers/gpu/drm/msm/dp/dp_power.c
> @@ -152,20 +152,9 @@ int dp_power_client_init(struct dp_power *dp_power)
>
>         power = container_of(dp_power, struct dp_power_private, dp_power);
>
> -       pm_runtime_enable(power->dev);
> -
>         return dp_power_clk_init(power);
>  }
>
> -void dp_power_client_deinit(struct dp_power *dp_power)
> -{
> -       struct dp_power_private *power;
> -
> -       power = container_of(dp_power, struct dp_power_private, dp_power);
> -
> -       pm_runtime_disable(power->dev);
> -}
> -
>  int dp_power_init(struct dp_power *dp_power)
>  {
>         int rc = 0;
> @@ -173,11 +162,7 @@ int dp_power_init(struct dp_power *dp_power)
>
>         power = container_of(dp_power, struct dp_power_private, dp_power);
>
> -       pm_runtime_get_sync(power->dev);
> -
>         rc = dp_power_clk_enable(dp_power, DP_CORE_PM, true);
> -       if (rc)
> -               pm_runtime_put_sync(power->dev);
>
>         return rc;
>  }
> @@ -189,7 +174,6 @@ int dp_power_deinit(struct dp_power *dp_power)
>         power = container_of(dp_power, struct dp_power_private, dp_power);
>
>         dp_power_clk_enable(dp_power, DP_CORE_PM, false);
> -       pm_runtime_put_sync(power->dev);
>         return 0;
>  }
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_power.h b/drivers/gpu/drm/msm/dp/dp_power.h
> index a3dec20..55ada51 100644
> --- a/drivers/gpu/drm/msm/dp/dp_power.h
> +++ b/drivers/gpu/drm/msm/dp/dp_power.h
> @@ -81,17 +81,6 @@ int dp_power_clk_enable(struct dp_power *power, enum dp_pm_type pm_type,
>  int dp_power_client_init(struct dp_power *power);
>
>  /**
> - * dp_power_clinet_deinit() - de-initialize clock and regulator modules
> - *
> - * @power: instance of power module
> - * return: 0 for success, error for failure.
> - *
> - * This API will de-initialize the DisplayPort's clocks and regulator
> - * modules.
> - */
> -void dp_power_client_deinit(struct dp_power *power);
> -
> -/**
>   * dp_power_get() - configure and get the DisplayPort power module data
>   *
>   * @parser: instance of parser module
> --
> 2.7.4
>


-- 
With best wishes
Dmitry

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