linux-kernel - Re: [PATCH] drm: bridge: dw_hdmi: Fix ELD is not updated issue

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Message-ID: <PAXPR04MB9448CDABEE9A1B55F8ADCC3AF409A@PAXPR04MB9448.eurprd04.prod.outlook.com>
Date:   Fri, 4 Aug 2023 02:03:24 +0000
From:   Sandor Yu <sandor.yu@....com>
To:     "neil.armstrong@...aro.org" <neil.armstrong@...aro.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "andrzej.hajda@...el.com" <andrzej.hajda@...el.com>,
        "rfoss@...nel.org" <rfoss@...nel.org>,
        "Laurent.pinchart@...asonboard.com" 
        <Laurent.pinchart@...asonboard.com>,
        "jonas@...boo.se" <jonas@...boo.se>,
        "jernej.skrabec@...il.com" <jernej.skrabec@...il.com>,
        "adrian.larumbe@...labora.com" <adrian.larumbe@...labora.com>,
        "treding@...dia.com" <treding@...dia.com>,
        "the.cheaterman@...il.com" <the.cheaterman@...il.com>,
        "l.stach@...gutronix.de" <l.stach@...gutronix.de>,
        "ville.syrjala@...ux.intel.com" <ville.syrjala@...ux.intel.com>,
        "cychiang@...omium.org" <cychiang@...omium.org>,
        "S.J. Wang" <shengjiu.wang@....com>
Subject: Re: [PATCH] drm: bridge: dw_hdmi: Fix ELD is not updated issue

Hi Neil,

Thanks for your comments,
 
> 
> Hi,
> 
> On 26/07/2023 03:48, Sandor Yu wrote:
> > The ELD (EDID-Like Data) is not updated when the HDMI cable is plugged
> > into different HDMI monitors.
> > This is because the EDID is not updated in the HDMI HPD function.
> > As a result, the ELD data remains unchanged and may not reflect the
> > capabilities of the newly connected HDMI sink device.
> >
> > To address this issue, the handle_plugged_change function should move
> > to the bridge_atomic_enable and bridge_atomic_disable functions.
> > Make sure the EDID is properly updated before updating ELD.
> >
> > Signed-off-by: Sandor Yu <Sandor.yu@....com>
> > ---
> >   drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 21 ++++-----------------
> >   1 file changed, 4 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > index 9a3db5234a0e0..6fa4848591226 100644
> > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > @@ -196,7 +196,6 @@ struct dw_hdmi {
> >
> >       hdmi_codec_plugged_cb plugged_cb;
> >       struct device *codec_dev;
> > -     enum drm_connector_status last_connector_result;
> >   };
> >
> >   #define HDMI_IH_PHY_STAT0_RX_SENSE \ @@ -235,7 +234,7 @@ int
> > dw_hdmi_set_plugged_cb(struct dw_hdmi *hdmi, hdmi_codec_plugged_cb
> fn,
> >       mutex_lock(&hdmi->mutex);
> >       hdmi->plugged_cb = fn;
> >       hdmi->codec_dev = codec_dev;
> > -     plugged = hdmi->last_connector_result ==
> connector_status_connected;
> > +     plugged = hdmi->connector.status == connector_status_connected;
> 
> Please use curr_conn instead, connector is not always valid.
curr_conn is NULL when dw_hdmi_set_plugged_cb is called by dw_hdmi_bridge_atomic_disable.
I will add the variable of last_connector_resul back to driver later.

B.R
Sandor 
> 
> >       handle_plugged_change(hdmi, plugged);
> >       mutex_unlock(&hdmi->mutex);
> >
> > @@ -2446,20 +2445,7 @@ static void dw_hdmi_update_phy_mask(struct
> > dw_hdmi *hdmi)
> >
> >   static enum drm_connector_status dw_hdmi_detect(struct dw_hdmi
> *hdmi)
> >   {
> > -     enum drm_connector_status result;
> > -
> > -     result = hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
> > -
> > -     mutex_lock(&hdmi->mutex);
> > -     if (result != hdmi->last_connector_result) {
> > -             dev_dbg(hdmi->dev, "read_hpd result: %d", result);
> > -             handle_plugged_change(hdmi,
> > -                                   result ==
> connector_status_connected);
> > -             hdmi->last_connector_result = result;
> > -     }
> > -     mutex_unlock(&hdmi->mutex);
> > -
> > -     return result;
> > +     return hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
> >   }
> >
> >   static struct edid *dw_hdmi_get_edid(struct dw_hdmi *hdmi, @@
> > -2958,6 +2944,7 @@ static void dw_hdmi_bridge_atomic_disable(struct
> drm_bridge *bridge,
> >       hdmi->curr_conn = NULL;
> >       dw_hdmi_update_power(hdmi);
> >       dw_hdmi_update_phy_mask(hdmi);
> > +     handle_plugged_change(hdmi, false);
> >       mutex_unlock(&hdmi->mutex);
> >   }
> >
> > @@ -2976,6 +2963,7 @@ static void
> dw_hdmi_bridge_atomic_enable(struct drm_bridge *bridge,
> >       hdmi->curr_conn = connector;
> >       dw_hdmi_update_power(hdmi);
> >       dw_hdmi_update_phy_mask(hdmi);
> > +     handle_plugged_change(hdmi, true);
> >       mutex_unlock(&hdmi->mutex);
> >   }
> >
> > @@ -3369,7 +3357,6 @@ struct dw_hdmi *dw_hdmi_probe(struct
> platform_device *pdev,
> >       hdmi->rxsense = true;
> >       hdmi->phy_mask = (u8)~(HDMI_PHY_HPD |
> HDMI_PHY_RX_SENSE);
> >       hdmi->mc_clkdis = 0x7f;
> > -     hdmi->last_connector_result = connector_status_disconnected;
> >
> >       mutex_init(&hdmi->mutex);
> >       mutex_init(&hdmi->audio_mutex);
> 
> Thanks,
> Neil