linux-kernel - Re: [PATCH v2 08/10] drm/bridge: anx7625: enable HPD interrupts

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Message-ID: <5hvpacx3qeqhjqemhqizws4esdhwg7reli77qey2nin2fggljp@ykgyayj2v3e6>
Date: Tue, 11 Mar 2025 17:39:48 +0200
From: Dmitry Baryshkov <lumag@...nel.org>
To: Ayushi Makhija <quic_amakhija@...cinc.com>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
	freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
	robdclark@...il.com, dmitry.baryshkov@...aro.org, sean@...rly.run, 
	marijn.suijten@...ainline.org, andersson@...nel.org, robh@...nel.org, robh+dt@...nel.org, 
	krzk+dt@...nel.org, konradybcio@...nel.org, conor+dt@...nel.org, 
	andrzej.hajda@...el.com, neil.armstrong@...aro.org, rfoss@...nel.org, 
	Laurent.pinchart@...asonboard.com, jonas@...boo.se, jernej.skrabec@...il.com, 
	quic_abhinavk@...cinc.com, quic_rajeevny@...cinc.com, quic_vproddut@...cinc.com, 
	quic_jesszhan@...cinc.com
Subject: Re: [PATCH v2 08/10] drm/bridge: anx7625: enable HPD interrupts

On Tue, Mar 11, 2025 at 05:54:43PM +0530, Ayushi Makhija wrote:
> When device enters the suspend state, it prevents
> HPD interrupts from occurring. To address this,
> add an additional PM runtime vote in hpd_enable().
> This vote is removed in hpd_disable().

Is it really enough to toggle the HPD interrupts? Is there any kind of
programming that should be moved to .hpd_enable() too (so that by
default the bridge doesn't generate HPD interrupts)?

> 
> Signed-off-by: Ayushi Makhija <quic_amakhija@...cinc.com>
> ---
>  drivers/gpu/drm/bridge/analogix/anx7625.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index 4be34d5c7a3b..764da1c1dc11 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -2474,6 +2474,22 @@ static const struct drm_edid *anx7625_bridge_edid_read(struct drm_bridge *bridge
>  	return anx7625_edid_read(ctx);
>  }
>  
> +static void anx7625_bridge_hpd_enable(struct drm_bridge *bridge)
> +{
> +	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> +	struct device *dev = ctx->dev;
> +
> +	pm_runtime_get_sync(dev);
> +}
> +
> +static void anx7625_bridge_hpd_disable(struct drm_bridge *bridge)
> +{
> +	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> +	struct device *dev = ctx->dev;
> +
> +	pm_runtime_put_sync(dev);
> +}
> +
>  static const struct drm_bridge_funcs anx7625_bridge_funcs = {
>  	.attach = anx7625_bridge_attach,
>  	.detach = anx7625_bridge_detach,
> @@ -2487,6 +2503,8 @@ static const struct drm_bridge_funcs anx7625_bridge_funcs = {
>  	.atomic_reset = drm_atomic_helper_bridge_reset,
>  	.detect = anx7625_bridge_detect,
>  	.edid_read = anx7625_bridge_edid_read,
> +	.hpd_enable = anx7625_bridge_hpd_enable,
> +	.hpd_disable = anx7625_bridge_hpd_disable,
>  };
>  
>  static int anx7625_register_i2c_dummy_clients(struct anx7625_data *ctx,
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry