linux-kernel - Re: [PATCH v11 1/4] drm/msm/dp: do not initialize phy until plugin interrupt received

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Message-ID: <CAE-0n51QbJHnOses5sF6xECR0gRZB1Fbi1KqoLG+61ZWH9BtOA@mail.gmail.com>
Date:   Thu, 13 Jan 2022 11:47:51 -0800
From:   Stephen Boyd <swboyd@...omium.org>
To:     Kuogee Hsieh <quic_khsieh@...cinc.com>, agross@...nel.org,
        airlied@...ux.ie, bjorn.andersson@...aro.org, daniel@...ll.ch,
        dmitry.baryshkov@...aro.org, dri-devel@...ts.freedesktop.org,
        robdclark@...il.com, sean@...rly.run, vkoul@...nel.org
Cc:     quic_abhinavk@...cinc.com, aravindh@...eaurora.org,
        quic_sbillaka@...cinc.com, freedreno@...ts.freedesktop.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v11 1/4] drm/msm/dp: do not initialize phy until plugin
 interrupt received

Quoting Kuogee Hsieh (2022-01-13 09:51:42)
>
> On 1/12/2022 8:13 PM, Stephen Boyd wrote:
> >>>> -       if (dp->usbpd->orientation == ORIENTATION_CC2)
> >>>> -               flip = true;
> >>>> +       dp_power_init(dp->power, false);
> >>>> +       dp_ctrl_reset_irq_ctrl(dp->ctrl, true);
> >>>> +
> >>>> +       /*
> >>>> +        * eDP is the embedded primary display and has its own phy
> >>>> +        * initialize phy immediately
> >>> Question still stands why we can't wait for hpd high from the eDP panel.
> >>> Also, I think "has its own phy" means that it's not part of a combo
> >>> USB+DP phy? Can you please clarify?
> >>>
> >>>> +        */
> >>>> +       if (dp->dp_display.connector_type == DRM_MODE_CONNECTOR_eDP)
> >>>> +               dp_display_host_phy_init(dp);
> >>>>
> >>>> -       dp_power_init(dp->power, flip);
> >>>> -       dp_ctrl_host_init(dp->ctrl, flip, reset);
> >>>>           dp_aux_init(dp->aux);
> >>>>           dp->core_initialized = true;
> >>>>    }
> >>>> @@ -1306,20 +1330,23 @@ static int dp_pm_resume(struct device *dev)
> >>>>           dp->hpd_state = ST_DISCONNECTED;
> >>>>
> >>>>           /* turn on dp ctrl/phy */
> >>>> -       dp_display_host_init(dp, true);
> >>>> +       dp_display_host_init(dp);
> >>>>
> >>>>           dp_catalog_ctrl_hpd_config(dp->catalog);
> >>>>
> >>>> -       /*
> >>>> -        * set sink to normal operation mode -- D0
> >>>> -        * before dpcd read
> >>>> -        */
> >>>> -       dp_link_psm_config(dp->link, &dp->panel->link_info, false);
> >>>>
> >>>>           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);
> >>> Why is the phy exited on resume when the link is still connected? Is
> >>> this supposed to be done only when the sink_count is 0? And how does
> >>> this interact with eDP where the phy is initialized by the call to
> >>> dp_display_host_init() earlier in this function.
> >>>
> >>>>           }
> >>>>
> >>>>           dp->link->sink_count = sink_count;
> > Any response to the above two comments?

??