Re: [PATCH v1 0/7] Add HPD support for Rockchip Analogix DP

From: "Heiko Stübner" <heiko@sntech.de>
To: Andrzej Hajda <andrzej.hajda@intel.com>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Robert Foss <rfoss@kernel.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
	Andy Yan <andy.yan@rock-chips.com>,
	Damon Ding <damon.ding@rock-chips.com>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Luca Ceresoli <luca.ceresoli@bootlin.com>,
	Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Sebastian Reichel <sebastian.reichel@collabora.com>,
	dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Damon Ding <damon.ding@rock-chips.com>
Subject: Re: [PATCH v1 0/7] Add HPD support for Rockchip Analogix DP
Date: Thu, 30 Jul 2026 20:49:43 +0200	[thread overview]
Message-ID: <2014349.VZ3vTMCxA0@diego> (raw)
In-Reply-To: <20260730032744.381566-1-damon.ding@rock-chips.com>

Hi Damon,

Am Donnerstag, 30. Juli 2026, 05:27:37 Mitteleuropäische Sommerzeit schrieb Damon Ding:
> This series improves the HPD (Hotplug Detect) interrupt handling in
> the Analogix DP driver to enable reliable native HPD pin detection on
> Rockchip platforms, and introduces platform-specific HPD detection
> schemes with fine-grained interrupt control.

[...]

> Tested on RK3576 with both native HPD pin and GPIO HPD configurations.
> 
> Native HPD pin mode:
> 
>   &edp {
>       status = "okay";
>       pinctrl-names = "default";
>       pinctrl-0 = <&edp_txm0_pins>;
>   };
> 
> GPIO HPD mode:
> 
>   &edp {
>       status = "okay";
>       pinctrl-names = "default";
>       pinctrl-0 = <&edp0_hpd>;
>       hpd-gpios = <&gpio4 RK_PC1 GPIO_ACTIVE_HIGH>;
>   };
> 
>   &pinctrl {
>       edp {
>           edp0_hpd: edp0-hpd {
>               rockchip,pins = <4 RK_PC1 0 &pcfg_pull_none>;
>           };
>       };
>   };

Yay and thanks a lot for working on that.

If I roll my display-port carrier board back to the analogix-dp being
the endpoint, this works exactly as expected :-) .

I can plug in the display at some point after the boot and have it
detected and setup correctly. Same with unplugging it while
the system is running. The connection status is correctly reported
in sysfs.

Though there is a caveat. When the eDP is not the last part, this does not
work anymore. The detect function always returns "connected" if there is
a next bridge available.

My board [0] has a physical DP connector on it, so models it as
dp-connector, but in that case the Analogix driver always reports being
connected.

Heiko

[0] https://lore.kernel.org/linux-rockchip/20251009225050.88192-3-heiko@sntech.de/
... same effect with hpd-gpios in either the edp node or dp-connector node

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