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Date:   Tue, 23 May 2023 05:35:04 -0700
From:   Bjorn Andersson <andersson@kernel.org>
To:     Kuogee Hsieh <quic_khsieh@quicinc.com>
Cc:     robdclark@gmail.com, sean@poorly.run, swboyd@chromium.org,
        dianders@chromium.org, vkoul@kernel.org, daniel@ffwll.ch,
        airlied@gmail.com, agross@kernel.org, dmitry.baryshkov@linaro.org,
        marijn.suijten@somainline.org, quic_abhinavk@quicinc.com,
        quic_jesszhan@quicinc.com, quic_sbillaka@quicinc.com,
        freedreno@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4] drm/msm/dp: enable HDP plugin/unplugged interrupts at
 hpd_enable/disable
Message-ID: <20230523123504.3xjssy6ktgrsdewi@ripper>
References: <1684796565-17138-1-git-send-email-quic_khsieh@quicinc.com>
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In-Reply-To: <1684796565-17138-1-git-send-email-quic_khsieh@quicinc.com>
Precedence: bulk

On Mon, May 22, 2023 at 04:02:45PM -0700, Kuogee Hsieh wrote:
> The internal_hpd flag is set to true by dp_bridge_hpd_enable() and set to
> false by dp_bridge_hpd_disable() to handle GPIO pinmuxed into DP controller
> case. HDP related interrupts can not be enabled until internal_hpd is set
> to true. At current implementation dp_display_config_hpd() will initialize
> DP host controller first followed by enabling HDP related interrupts if
> internal_hpd was true at that time. Enable HDP related interrupts depends on
> internal_hpd status may leave system with DP driver host is in running state
> but without HDP related interrupts being enabled. This will prevent external
> display from being detected. Eliminated this dependency by moving HDP related
> interrupts enable/disable be done at dp_bridge_hpd_enable/disable() directly
> regardless of internal_hpd status.
> 
> Changes in V3:
> -- dp_catalog_ctrl_hpd_enable() and dp_catalog_ctrl_hpd_disable()
> -- rewording ocmmit text
> 
> Changes in V4:
> -- replace dp_display_config_hpd() with dp_display_host_start()
> -- move enable_irq() at dp_display_host_start();

I think what Dmitry was asking for was that you remove the disable_irq()
from dp_display_request_irq(), but perhaps I missed some argumentation
for why that can't/shouldn't be done?

> 

Either way, this looks good and it works for me.

Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Tested-by: Bjorn Andersson <andersson@kernel.org>

Thanks,
Bjorn

> Fixes: cd198caddea7 ("drm/msm/dp: Rely on hpd_enable/disable callbacks")
> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_catalog.c | 15 +++++++++-
>  drivers/gpu/drm/msm/dp/dp_catalog.h |  3 +-
>  drivers/gpu/drm/msm/dp/dp_display.c | 58 +++++++++++++------------------------
>  3 files changed, 36 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c
> index 7a8cf1c..5142aeb 100644
> --- a/drivers/gpu/drm/msm/dp/dp_catalog.c
> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
> @@ -620,7 +620,7 @@ void dp_catalog_hpd_config_intr(struct dp_catalog *dp_catalog,
>  				config & DP_DP_HPD_INT_MASK);
>  }
>  
> -void dp_catalog_ctrl_hpd_config(struct dp_catalog *dp_catalog)
> +void dp_catalog_ctrl_hpd_enable(struct dp_catalog *dp_catalog)
>  {
>  	struct dp_catalog_private *catalog = container_of(dp_catalog,
>  				struct dp_catalog_private, dp_catalog);
> @@ -635,6 +635,19 @@ void dp_catalog_ctrl_hpd_config(struct dp_catalog *dp_catalog)
>  	dp_write_aux(catalog, REG_DP_DP_HPD_CTRL, DP_DP_HPD_CTRL_HPD_EN);
>  }
>  
> +void dp_catalog_ctrl_hpd_disable(struct dp_catalog *dp_catalog)
> +{
> +	struct dp_catalog_private *catalog = container_of(dp_catalog,
> +				struct dp_catalog_private, dp_catalog);
> +
> +	u32 reftimer = dp_read_aux(catalog, REG_DP_DP_HPD_REFTIMER);
> +
> +	reftimer &= ~DP_DP_HPD_REFTIMER_ENABLE;
> +	dp_write_aux(catalog, REG_DP_DP_HPD_REFTIMER, reftimer);
> +
> +	dp_write_aux(catalog, REG_DP_DP_HPD_CTRL, 0);
> +}
> +
>  static void dp_catalog_enable_sdp(struct dp_catalog_private *catalog)
>  {
>  	/* trigger sdp */
> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.h b/drivers/gpu/drm/msm/dp/dp_catalog.h
> index 82376a2..38786e8 100644
> --- a/drivers/gpu/drm/msm/dp/dp_catalog.h
> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.h
> @@ -104,7 +104,8 @@ bool dp_catalog_ctrl_mainlink_ready(struct dp_catalog *dp_catalog);
>  void dp_catalog_ctrl_enable_irq(struct dp_catalog *dp_catalog, bool enable);
>  void dp_catalog_hpd_config_intr(struct dp_catalog *dp_catalog,
>  			u32 intr_mask, bool en);
> -void dp_catalog_ctrl_hpd_config(struct dp_catalog *dp_catalog);
> +void dp_catalog_ctrl_hpd_enable(struct dp_catalog *dp_catalog);
> +void dp_catalog_ctrl_hpd_disable(struct dp_catalog *dp_catalog);
>  void dp_catalog_ctrl_config_psr(struct dp_catalog *dp_catalog);
>  void dp_catalog_ctrl_set_psr(struct dp_catalog *dp_catalog, bool enter);
>  u32 dp_catalog_link_is_connected(struct dp_catalog *dp_catalog);
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index 3e13acdf..370632b 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -615,12 +615,6 @@ static int dp_hpd_plug_handle(struct dp_display_private *dp, u32 data)
>  		dp->hpd_state = ST_MAINLINK_READY;
>  	}
>  
> -	/* enable HDP irq_hpd/replug interrupt */
> -	if (dp->dp_display.internal_hpd)
> -		dp_catalog_hpd_config_intr(dp->catalog,
> -					   DP_DP_IRQ_HPD_INT_MASK | DP_DP_HPD_REPLUG_INT_MASK,
> -					   true);
> -
>  	drm_dbg_dp(dp->drm_dev, "After, type=%d hpd_state=%d\n",
>  			dp->dp_display.connector_type, state);
>  	mutex_unlock(&dp->event_mutex);
> @@ -658,12 +652,6 @@ static int dp_hpd_unplug_handle(struct dp_display_private *dp, u32 data)
>  	drm_dbg_dp(dp->drm_dev, "Before, type=%d hpd_state=%d\n",
>  			dp->dp_display.connector_type, state);
>  
> -	/* disable irq_hpd/replug interrupts */
> -	if (dp->dp_display.internal_hpd)
> -		dp_catalog_hpd_config_intr(dp->catalog,
> -					   DP_DP_IRQ_HPD_INT_MASK | DP_DP_HPD_REPLUG_INT_MASK,
> -					   false);
> -
>  	/* unplugged, no more irq_hpd handle */
>  	dp_del_event(dp, EV_IRQ_HPD_INT);
>  
> @@ -687,10 +675,6 @@ static int dp_hpd_unplug_handle(struct dp_display_private *dp, u32 data)
>  		return 0;
>  	}
>  
> -	/* disable HPD plug interrupts */
> -	if (dp->dp_display.internal_hpd)
> -		dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_PLUG_INT_MASK, false);
> -
>  	/*
>  	 * We don't need separate work for disconnect as
>  	 * connect/attention interrupts are disabled
> @@ -706,10 +690,6 @@ static int dp_hpd_unplug_handle(struct dp_display_private *dp, u32 data)
>  	/* signal the disconnect event early to ensure proper teardown */
>  	dp_display_handle_plugged_change(&dp->dp_display, false);
>  
> -	/* enable HDP plug interrupt to prepare for next plugin */
> -	if (dp->dp_display.internal_hpd)
> -		dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_PLUG_INT_MASK, true);
> -
>  	drm_dbg_dp(dp->drm_dev, "After, type=%d hpd_state=%d\n",
>  			dp->dp_display.connector_type, state);
>  
> @@ -1082,18 +1062,10 @@ void msm_dp_snapshot(struct msm_disp_state *disp_state, struct msm_dp *dp)
>  	mutex_unlock(&dp_display->event_mutex);
>  }
>  
> -static void dp_display_config_hpd(struct dp_display_private *dp)
> +static void dp_display_host_start(struct dp_display_private *dp)
>  {
>  
>  	dp_display_host_init(dp);
> -	dp_catalog_ctrl_hpd_config(dp->catalog);
> -
> -	/* Enable plug and unplug interrupts only if requested */
> -	if (dp->dp_display.internal_hpd)
> -		dp_catalog_hpd_config_intr(dp->catalog,
> -				DP_DP_HPD_PLUG_INT_MASK |
> -				DP_DP_HPD_UNPLUG_INT_MASK,
> -				true);
>  
>  	/* Enable interrupt first time
>  	 * we are leaving dp clocks on during disconnect
> @@ -1176,7 +1148,7 @@ static int hpd_event_thread(void *data)
>  
>  		switch (todo->event_id) {
>  		case EV_HPD_INIT_SETUP:
> -			dp_display_config_hpd(dp_priv);
> +			dp_display_host_start(dp_priv);
>  			break;
>  		case EV_HPD_PLUG_INT:
>  			dp_hpd_plug_handle(dp_priv, todo->data);
> @@ -1394,13 +1366,8 @@ static int dp_pm_resume(struct device *dev)
>  	/* turn on dp ctrl/phy */
>  	dp_display_host_init(dp);
>  
> -	dp_catalog_ctrl_hpd_config(dp->catalog);
> -
> -	if (dp->dp_display.internal_hpd)
> -		dp_catalog_hpd_config_intr(dp->catalog,
> -				DP_DP_HPD_PLUG_INT_MASK |
> -				DP_DP_HPD_UNPLUG_INT_MASK,
> -				true);
> +	if (dp_display->is_edp)
> +		dp_catalog_ctrl_hpd_enable(dp->catalog);
>  
>  	if (dp_catalog_link_is_connected(dp->catalog)) {
>  		/*
> @@ -1568,7 +1535,7 @@ static int dp_display_get_next_bridge(struct msm_dp *dp)
>  
>  	if (aux_bus && dp->is_edp) {
>  		dp_display_host_init(dp_priv);
> -		dp_catalog_ctrl_hpd_config(dp_priv->catalog);
> +		dp_catalog_ctrl_hpd_enable(dp_priv->catalog);
>  		dp_display_host_phy_init(dp_priv);
>  		enable_irq(dp_priv->irq);
>  
> @@ -1801,16 +1768,31 @@ void dp_bridge_hpd_enable(struct drm_bridge *bridge)
>  {
>  	struct msm_dp_bridge *dp_bridge = to_dp_bridge(bridge);
>  	struct msm_dp *dp_display = dp_bridge->dp_display;
> +	struct dp_display_private *dp = container_of(dp_display, struct dp_display_private, dp_display);
> +
> +	mutex_lock(&dp->event_mutex);
> +	dp_catalog_ctrl_hpd_enable(dp->catalog);
> +
> +	/* enable HDP interrupts */
> +	dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_INT_MASK, true);
>  
>  	dp_display->internal_hpd = true;
> +	mutex_unlock(&dp->event_mutex);
>  }
>  
>  void dp_bridge_hpd_disable(struct drm_bridge *bridge)
>  {
>  	struct msm_dp_bridge *dp_bridge = to_dp_bridge(bridge);
>  	struct msm_dp *dp_display = dp_bridge->dp_display;
> +	struct dp_display_private *dp = container_of(dp_display, struct dp_display_private, dp_display);
> +
> +	mutex_lock(&dp->event_mutex);
> +	/* disable HDP interrupts */
> +	dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_INT_MASK, false);
> +	dp_catalog_ctrl_hpd_disable(dp->catalog);
>  
>  	dp_display->internal_hpd = false;
> +	mutex_unlock(&dp->event_mutex);
>  }
>  
>  void dp_bridge_hpd_notify(struct drm_bridge *bridge,
> -- 
> 2.7.4
>