linux-kernel - Re: [PATCH v6 7/8] drm: dw-hdmi: use cec_notifier_conn

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Date:   Tue, 13 Aug 2019 13:37:53 +0200
From:   Hans Verkuil <hverkuil-cisco@...all.nl>
To:     Dariusz Marcinkiewicz <darekm@...gle.com>,
        dri-devel@...ts.freedesktop.org, linux-media@...r.kernel.org
Cc:     Andrzej Hajda <a.hajda@...sung.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Sam Ravnborg <sam@...nborg.org>,
        Douglas Anderson <dianders@...omium.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 7/8] drm: dw-hdmi: use cec_notifier_conn_(un)register

On 8/13/19 1:02 PM, Dariusz Marcinkiewicz wrote:
> Use the new cec_notifier_conn_(un)register() functions to
> (un)register the notifier for the HDMI connector, and fill in
> the cec_connector_info.
> 
> Changes since v4:
> 	- typo fix
> Changes since v2:
> 	- removed unnecessary NULL check before a call to
> 	cec_notifier_conn_unregister,
> 	- use cec_notifier_phys_addr_invalidate to invalidate physical
> 	address.
> Changes since v1:
> 	Add memory barrier to make sure that the notifier
> 	becomes visible to the irq thread once it is fully
> 	constructed.
> 
> Signed-off-by: Dariusz Marcinkiewicz <darekm@...gle.com>
> Tested-by: Hans Verkuil <hverkuil-cisco@...all.nl>
> ---
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 36 ++++++++++++++---------
>  1 file changed, 22 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index 83b94b66e464e..c00184700bb9d 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -2194,6 +2194,8 @@ static int dw_hdmi_bridge_attach(struct drm_bridge *bridge)
>  	struct dw_hdmi *hdmi = bridge->driver_private;
>  	struct drm_encoder *encoder = bridge->encoder;
>  	struct drm_connector *connector = &hdmi->connector;
> +	struct cec_connector_info conn_info;
> +	struct cec_notifier *notifier;
>  
>  	connector->interlace_allowed = 1;
>  	connector->polled = DRM_CONNECTOR_POLL_HPD;
> @@ -2207,6 +2209,18 @@ static int dw_hdmi_bridge_attach(struct drm_bridge *bridge)
>  
>  	drm_connector_attach_encoder(connector, encoder);
>  
> +	cec_fill_conn_info_from_drm(&conn_info, connector);
> +
> +	notifier = cec_notifier_conn_register(hdmi->dev, NULL, &conn_info);
> +	if (!notifier)
> +		return -ENOMEM;
> +	/*
> +	 * Make sure that dw_hdmi_irq thread does see the notifier
> +	 * when it fully constructed.
> +	 */
> +	smp_wmb();
> +	hdmi->cec_notifier = notifier;
> +
>  	return 0;
>  }
>  
> @@ -2373,9 +2387,13 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
>  				       phy_stat & HDMI_PHY_HPD,
>  				       phy_stat & HDMI_PHY_RX_SENSE);
>  
> -		if ((phy_stat & (HDMI_PHY_RX_SENSE | HDMI_PHY_HPD)) == 0)
> -			cec_notifier_set_phys_addr(hdmi->cec_notifier,
> -						   CEC_PHYS_ADDR_INVALID);
> +		if ((phy_stat & (HDMI_PHY_RX_SENSE | HDMI_PHY_HPD)) == 0) {
> +			struct cec_notifier *notifier;
> +
> +			notifier = READ_ONCE(hdmi->cec_notifier);
> +			if (notifier)
> +				cec_notifier_phys_addr_invalidate(notifier);
> +		}
>  	}
>  
>  	if (intr_stat & HDMI_IH_PHY_STAT0_HPD) {
> @@ -2693,12 +2711,6 @@ __dw_hdmi_probe(struct platform_device *pdev,
>  	if (ret)
>  		goto err_iahb;
>  
> -	hdmi->cec_notifier = cec_notifier_get(dev);
> -	if (!hdmi->cec_notifier) {
> -		ret = -ENOMEM;
> -		goto err_iahb;
> -	}
> -
>  	/*
>  	 * To prevent overflows in HDMI_IH_FC_STAT2, set the clk regenerator
>  	 * N and cts values before enabling phy
> @@ -2796,9 +2808,6 @@ __dw_hdmi_probe(struct platform_device *pdev,
>  		hdmi->ddc = NULL;
>  	}
>  
> -	if (hdmi->cec_notifier)
> -		cec_notifier_put(hdmi->cec_notifier);
> -
>  	clk_disable_unprepare(hdmi->iahb_clk);
>  	if (hdmi->cec_clk)
>  		clk_disable_unprepare(hdmi->cec_clk);
> @@ -2820,8 +2829,7 @@ static void __dw_hdmi_remove(struct dw_hdmi *hdmi)
>  	/* Disable all interrupts */
>  	hdmi_writeb(hdmi, ~0, HDMI_IH_MUTE_PHY_STAT0);
>  
> -	if (hdmi->cec_notifier)
> -		cec_notifier_put(hdmi->cec_notifier);
> +	cec_notifier_conn_unregister(hdmi->cec_notifier);

Russell's review caused me to take another look at this series, and it made
wonder if cec_notifier_conn_unregister() shouldn't be called from bridge_detach?

Regards,

	Hans

>  
>  	clk_disable_unprepare(hdmi->iahb_clk);
>  	clk_disable_unprepare(hdmi->isfr_clk);
>