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

[Kuogee Hsieh <quic_khsieh@quicinc.com>]

On 9/15/2023 6:21 PM, Dmitry Baryshkov wrote:
> On Sat, 16 Sept 2023 at 00:38, Kuogee Hsieh <quic_khsieh@quicinc.com> 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?

1) for edp, dp_bridge_atomic_enable(), called from framework, to start 
link training and bring up display.

2) for external DP, HPD_PLUG_INT will be generated to start link 
training and bring up display.

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

1) dp_pm_prepare() is called to make sure eDP/DP related power/clocks 
are off and set hpd_state  to ST_SUSPENDED and nothing else.

2) dp_pm_completed() is called to set hpd_state to ST_ST_DISCONNECTED 
(default state) and nothing else.

I think both are doing proper action.


>
>> 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@quicinc.com>
>> ---
>>   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
>>
>