RE: [PATCH v2] drm/bridge: adv7511: Clear HPD IRQ during atomic_enable()

[Biju Das]

Hi All,

> -----Original Message-----
> From: Biju <biju.das.au@xxxxxxxxx>
> Sent: 22 April 2026 13:15
> Subject: [PATCH v2] drm/bridge: adv7511: Clear HPD IRQ during atomic_enable()
> 
> From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> 
> On RZ/G3E SMARC EVK, suspend-to-RAM via PSCI powers down the ADV7535 chip entirely, causing the HPD status
> bit to be in a stale state on resume. When the display controller driver's system PM resume callback
> invokes drm_mode_config_helper_resume(), it calls the bridge's atomic_enable(), but the stale HPD IRQ is
> never cleared, leading to incorrect behaviour.
> 
> Clear the HPD status bit in adv7511_bridge_atomic_enable() after powering on, so that any HPD interrupt
> latched before or during power-loss is dismissed before normal operation resumes.
> 
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> ---
> Tested HPD, s2idle and s2ram on RZ/G3L SMARC EVK connected to ADV7535 on both polling and IRQ mode.
> v1->v2:
>  * Dropped PM support instead clearing latched HPD status bit in
>    adv7511_bridge_atomic_enable()
>  * Dropped suspended variable from struct adv7511.
>  * Updated comment in adv7511_bridge_atomic_enable().
>  * Clearing the HPD status bit unconditionally as there is no harm.
>  * Updated commit header and description.
>  * Dropped the tags.
> ---
>  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> index 6bd76c1fb007..7663814b4032 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> @@ -792,6 +792,13 @@ static void adv7511_bridge_atomic_enable(struct drm_bridge *bridge,
> 
>  	adv7511_power_on(adv);
> 
> +	/*
> +	 * Clear the HPD status bit (ADV7511_INT0_HPD), so that any HPD
> +	 * interrupt latched before or during power loss is dismissed before
> +	 * normal operation resumes.
> +	 */
> +	regmap_write(adv->regmap, ADV7511_REG_INT(0), ADV7511_INT0_HPD);
> +
>  	connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
>  	if (WARN_ON(!connector))
>  		return;
> --
> 2.43.0

Gentle ping.

Cheers,
Biju