linux-kernel - Re: [PATCH v3 3/7] drm/msm/dp: use drm_bridge_hpd

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Message-ID: <CAA8EJpof+dp_d_5-oADuA7RNU7ut=TKLY5Fw12EjxaSa2S+=rg@mail.gmail.com>
Date:   Tue, 19 Sep 2023 12:45:55 +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 v3 3/7] drm/msm/dp: use drm_bridge_hpd_notify() to report
 HPD status changes

On Mon, 18 Sept 2023 at 23:16, Kuogee Hsieh <quic_khsieh@...cinc.com> wrote:
>
>
> On 9/15/2023 5:41 PM, Dmitry Baryshkov wrote:
> > On Sat, 16 Sept 2023 at 00:38, Kuogee Hsieh <quic_khsieh@...cinc.com> wrote:
> >> Currently DP driver use drm_helper_hpd_irq_event(), bypassing drm bridge
> >> framework, to report HPD status changes to user space frame work.
> >> Replace it with drm_bridge_hpd_notify() since DP driver is part of drm
> >> bridge.
> >>
> >> Signed-off-by: Kuogee Hsieh <quic_khsieh@...cinc.com>
> > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> >
> > Also see the comment below.
> >
> >> ---
> >>   drivers/gpu/drm/msm/dp/dp_display.c | 20 ++------------------
> >>   1 file changed, 2 insertions(+), 18 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> >> index 18d16c7..59f9d85 100644
> >> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> >> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> >> @@ -356,26 +356,10 @@ static bool dp_display_is_sink_count_zero(struct dp_display_private *dp)
> >>                  (dp->link->sink_count == 0);
> >>   }
> >>
> >> -static void dp_display_send_hpd_event(struct msm_dp *dp_display)
> >> -{
> >> -       struct dp_display_private *dp;
> >> -       struct drm_connector *connector;
> >> -
> >> -       dp = container_of(dp_display, struct dp_display_private, dp_display);
> >> -
> >> -       connector = dp->dp_display.connector;
> >> -       drm_helper_hpd_irq_event(connector->dev);
> >> -}
> >> -
> >>   static int dp_display_send_hpd_notification(struct dp_display_private *dp,
> >>                                              bool hpd)
> >>   {
> >> -       if ((hpd && dp->dp_display.link_ready) ||
> >> -                       (!hpd && !dp->dp_display.link_ready)) {
> >> -               drm_dbg_dp(dp->drm_dev, "HPD already %s\n",
> >> -                               (hpd ? "on" : "off"));
> >> -               return 0;
> >> -       }
> >> +       struct drm_bridge *bridge = dp->dp_display.bridge;
> >>
> >>          /* reset video pattern flag on disconnect */
> >>          if (!hpd)
> > Note, this part (resetting the video_test and setting of is_connected)
> > should be moved to the dp_bridge_hpd_notify() too. Please ignore this
> > comment if this is handled later in the series.
>
> I think keep them here is better since eDP does not populate hpd_enable,
> hpd_disable and hpd_notify at edp_bridge_ops at drm_bridge_attach().
>
> Keep them here will work for both eDP and DP.

Having them here doesn't work for DP-with-external-bridges, which will
not use dp_display_send_hpd_notification.

>
>
> >
> >
> >> @@ -385,7 +369,7 @@ static int dp_display_send_hpd_notification(struct dp_display_private *dp,
> >>
> >>          drm_dbg_dp(dp->drm_dev, "type=%d hpd=%d\n",
> >>                          dp->dp_display.connector_type, hpd);
> >> -       dp_display_send_hpd_event(&dp->dp_display);
> >> +       drm_bridge_hpd_notify(bridge, dp->dp_display.link_ready);
> >>
> >>          return 0;
> >>   }
> >> --
> >> 2.7.4
> >>
> >



-- 
With best wishes
Dmitry