Re: [PATCH v3] drm/msm/dp: enable HDP plugin/unplugged interrupts at hpd_enable/disable

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

On 23/05/2023 01:05, Bjorn Andersson wrote:
> On Mon, May 22, 2023 at 02:31:32PM -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.
>
> Thanks Kuogee, this looks quite good to me. But...
>
> > Changes in V3:
> > -- dp_catalog_ctrl_hpd_enable() and dp_catalog_ctrl_hpd_disable()
> > -- rewording ocmmit text
> >
> > Fixes: cd198caddea7 ("drm/msm/dp: Rely on hpd_enable/disable callbacks")
> > Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
> > ---
> >   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 | 70 +++++++++++--------------------------
> >   3 files changed, 37 insertions(+), 51 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..69bbc5f 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);
> >   
> > @@ -1082,26 +1062,6 @@ 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)
> > -{
> > -
> > -	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
> > -	 * and never disable interrupt
> > -	 */
> > -	enable_irq(dp->irq);
>
> ...we need dp->irq enabled for handling the other interrupts, otherwise
> e.g. AUX transfers will time out.
>
> I added enable_irq(dp_priv->irq) to the EV_HPD_INIT_SETUP case below,
> just for testing, and with that the patch seems to be working fine.
>
>
> Is there any reason why we need to delay its enablement to after we
> unmask the HPD interrupts?

As I wrote, I'd probably prefer to see enable_irq() and disable_irq() 
calls gone.

> Regards,
> Bjorn
>
> > -}
> > -
> >   void dp_display_set_psr(struct msm_dp *dp_display, bool enter)
> >   {
> >   	struct dp_display_private *dp;
> > @@ -1176,7 +1136,7 @@ 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_init(dp_priv);
> >   			break;
> >   		case EV_HPD_PLUG_INT:
> >   			dp_hpd_plug_handle(dp_priv, todo->data);
> > @@ -1394,13 +1354,8 @@ 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 +1523,7 @@ 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 +1756,33 @@ 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);
> > +
> > +	enable_irq(dp->irq);
> >   
> >   	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

--
With best wishes
Dmitry