Re: [PATCH v3 6/7] drm/msm/dp: add pm_runtime_force_suspend()/resume()

[Dmitry Baryshkov]

On Sat, 16 Sept 2023 at 00:38, Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx> wrote:
>
> Add pm_runtime_force_suspend()/resume() to complete incorporating pm
> runtime framework into DP driver. Both dp_pm_prepare() and dp_pm_complete()
> are added to set hpd_state to correct state. After resume, DP driver will
> re training its main link after .hpd_enable() callback enabled HPD
> interrupts and bring up display accordingly.

How will it re-train the main link? What is the code path for that?

I think this is a misuse for prepare/complete callbacks, at least
judging from their documentation.

>
> Changes in v3:
> -- replace dp_pm_suspend() with pm_runtime_force_suspend()
> -- replace dp_pm_resume() with pm_runtime_force_resume()
>
> Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
> ---
>  drivers/gpu/drm/msm/dp/dp_display.c | 87 +++++--------------------------------
>  1 file changed, 10 insertions(+), 77 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index b6992202..b58cb02 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -1333,101 +1333,35 @@ static int dp_pm_runtime_resume(struct device *dev)
>         return 0;
>  }
>
> -static int dp_pm_resume(struct device *dev)
> +static void dp_pm_complete(struct device *dev)
>  {
> -       struct platform_device *pdev = to_platform_device(dev);
> -       struct msm_dp *dp_display = platform_get_drvdata(pdev);
> -       struct dp_display_private *dp;
> -       int sink_count = 0;
> -
> -       dp = container_of(dp_display, struct dp_display_private, dp_display);
> +       struct dp_display_private *dp = dev_get_dp_display_private(dev);
>
>         mutex_lock(&dp->event_mutex);
>
>         drm_dbg_dp(dp->drm_dev,
> -               "Before, type=%d core_inited=%d phy_inited=%d power_on=%d\n",
> +               "type=%d core_inited=%d phy_inited=%d power_on=%d\n",
>                 dp->dp_display.connector_type, dp->core_initialized,
> -               dp->phy_initialized, dp_display->power_on);
> +               dp->phy_initialized, dp->dp_display.power_on);
>
>         /* start from disconnected state */
>         dp->hpd_state = ST_DISCONNECTED;
>
> -       /* turn on dp ctrl/phy */
> -       dp_display_host_init(dp);
> -
> -       if (dp_display->is_edp)
> -               dp_catalog_ctrl_hpd_enable(dp->catalog);
> -
> -       if (dp_catalog_link_is_connected(dp->catalog)) {
> -               /*
> -                * set sink to normal operation mode -- D0
> -                * before dpcd read
> -                */
> -               dp_display_host_phy_init(dp);
> -               dp_link_psm_config(dp->link, &dp->panel->link_info, false);
> -               sink_count = drm_dp_read_sink_count(dp->aux);
> -               if (sink_count < 0)
> -                       sink_count = 0;
> -
> -               dp_display_host_phy_exit(dp);
> -       }
> -
> -       dp->link->sink_count = sink_count;
> -       /*
> -        * can not declared display is connected unless
> -        * HDMI cable is plugged in and sink_count of
> -        * dongle become 1
> -        * also only signal audio when disconnected
> -        */
> -       if (dp->link->sink_count) {
> -               dp->dp_display.link_ready = true;
> -       } else {
> -               dp->dp_display.link_ready = false;
> -               dp_display_handle_plugged_change(dp_display, false);
> -       }
> -
> -       drm_dbg_dp(dp->drm_dev,
> -               "After, type=%d sink=%d conn=%d core_init=%d phy_init=%d power=%d\n",
> -               dp->dp_display.connector_type, dp->link->sink_count,
> -               dp->dp_display.link_ready, dp->core_initialized,
> -               dp->phy_initialized, dp_display->power_on);
> -
>         mutex_unlock(&dp->event_mutex);
> -
> -       return 0;
>  }
>
> -static int dp_pm_suspend(struct device *dev)
> +static int dp_pm_prepare(struct device *dev)
>  {
> -       struct platform_device *pdev = to_platform_device(dev);
> -       struct msm_dp *dp_display = platform_get_drvdata(pdev);
> -       struct dp_display_private *dp;
> -
> -       dp = container_of(dp_display, struct dp_display_private, dp_display);
> +       struct dp_display_private *dp = dev_get_dp_display_private(dev);
>
>         mutex_lock(&dp->event_mutex);
>
> -       drm_dbg_dp(dp->drm_dev,
> -               "Before, type=%d core_inited=%d  phy_inited=%d power_on=%d\n",
> -               dp->dp_display.connector_type, dp->core_initialized,
> -               dp->phy_initialized, dp_display->power_on);
> -
>         /* mainlink enabled */
>         if (dp_power_clk_status(dp->power, DP_CTRL_PM))
>                 dp_ctrl_off_link_stream(dp->ctrl);
>
> -       dp_display_host_phy_exit(dp);
> -
> -       /* host_init will be called at pm_resume */
> -       dp_display_host_deinit(dp);
> -
>         dp->hpd_state = ST_SUSPENDED;
>
> -       drm_dbg_dp(dp->drm_dev,
> -               "After, type=%d core_inited=%d phy_inited=%d power_on=%d\n",
> -               dp->dp_display.connector_type, dp->core_initialized,
> -               dp->phy_initialized, dp_display->power_on);
> -
>         mutex_unlock(&dp->event_mutex);
>
>         return 0;
> @@ -1435,8 +1369,10 @@ 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,
> +       SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> +                                pm_runtime_force_resume)
> +       .prepare = dp_pm_prepare,
> +       .complete = dp_pm_complete,
>  };
>
>  static struct platform_driver dp_display_driver = {
> @@ -1670,9 +1606,6 @@ void dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
>
>         dp_display = container_of(dp, struct dp_display_private, dp_display);
>
> -       if (dp->is_edp)
> -               dp_hpd_unplug_handle(dp_display, 0);
> -
>         mutex_lock(&dp_display->event_mutex);
>
>         state = dp_display->hpd_state;
> --
> 2.7.4
>


-- 
With best wishes
Dmitry