From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gloria.sntech.de (gloria.sntech.de [185.11.138.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0D64930C158; Fri, 31 Jul 2026 09:24:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.11.138.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785489862; cv=none; b=ozb/CcqejOVo40D+FqyyYibCJXCayyBxLlvFg5pKtxVqUNUt4VvxAYFhVlfdz3nxdnsQJXPtMPMy7N4pG3kN1Ida8pujGijePP6z62SzoNpy2gOMlceicCd9kEPqgrWOJbl2zZQNu/f0PjR56hLvJCQkQc76OL89eLr4AS0UIPo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785489862; c=relaxed/simple; bh=22PhUAgYSD/3JPDx6ODdZjfQHOw9Ngd7km3YMpnUdbc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=lVN3CAuY35OYhT2h1Udx69HsK5kJBaNrDb56xUlh2aOgUqEsb5Jf+qooKnZwAAPPkblymwdk2JZsLib5vAmCnn+FCfvTdozT4z97Ihp3FMT+5yMaPrOOc8gxEmIqZ4fynZl4/9D0VbQAO01N/sYdPC3+yA4uF0jcktKrSMDgmBI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=sntech.de; spf=pass smtp.mailfrom=sntech.de; dkim=pass (2048-bit key) header.d=sntech.de header.i=@sntech.de header.b=B/JJqca+; arc=none smtp.client-ip=185.11.138.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=sntech.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sntech.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sntech.de header.i=@sntech.de header.b="B/JJqca+" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sntech.de; s=gloria202408; h=Content-Type:Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Reply-To; bh=oFHrJog3XUbgCM9lluuv2EFqo2uk4k0XFykLEC/aems=; b=B/JJqca+bPMKWjUiWl5Ddpdrou /GV08FXx0rPSiUWzPmjNIMqI0Yz+rT5qhA02yhHndBqmS2OD2DhNX0ahpXwavNj+e48+Tv0Gu0y71 MEH4nbUPhcSxHaH8jdJWMPrtTNN2OFIsS9o1gN33KtBkmdPy/a+fJsy+yYUODYWD9AP0zO0/mHM0W pLY1m4cyT75b+EinDrycvjePS+9ujH0A4J8QhevV9UaGdtEdMVp8cWWDMIagU5ZIk32lZ0FmauK+P qLHJatO/RaIwRJoVgGawN2vA34bmRRp1/xn7+1xhIbaqtC60E0hRPMZwIpW+ACoiynPNImVx9KOAY Fv9/JhCA==; From: Heiko =?UTF-8?B?U3TDvGJuZXI=?= To: Andrzej Hajda , Neil Armstrong , Robert Foss , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Andy Yan , Damon Ding Cc: Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Dmitry Baryshkov , Marek Szyprowski , Sebastian Reichel , 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 Subject: Re: [PATCH v1 0/7] Add HPD support for Rockchip Analogix DP Date: Fri, 31 Jul 2026 11:23:43 +0200 Message-ID: <24131962.ssLaC8jLEa@diego> In-Reply-To: References: <20260730032744.381566-1-damon.ding@rock-chips.com> <2014349.VZ3vTMCxA0@diego> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Hi Damon, Am Freitag, 31. Juli 2026, 05:08:45 Mitteleurop=C3=A4ische Sommerzeit schri= eb Damon Ding: > On 7/31/2026 2:49 AM, Heiko St=C3=BCbner wrote: > > Am Donnerstag, 30. Juli 2026, 05:27:37 Mitteleurop=C3=A4ische Sommerzei= t 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. > >=20 > > [...] > >=20 > >> Tested on RK3576 with both native HPD pin and GPIO HPD configurations. > >> > >> Native HPD pin mode: > >> > >> &edp { > >> status =3D "okay"; > >> pinctrl-names =3D "default"; > >> pinctrl-0 =3D <&edp_txm0_pins>; > >> }; > >> > >> GPIO HPD mode: > >> > >> &edp { > >> status =3D "okay"; > >> pinctrl-names =3D "default"; > >> pinctrl-0 =3D <&edp0_hpd>; > >> hpd-gpios =3D <&gpio4 RK_PC1 GPIO_ACTIVE_HIGH>; > >> }; > >> > >> &pinctrl { > >> edp { > >> edp0_hpd: edp0-hpd { > >> rockchip,pins =3D <4 RK_PC1 0 &pcfg_pull_none>; > >> }; > >> }; > >> }; > >=20 > > Yay and thanks a lot for working on that. > >=20 > > If I roll my display-port carrier board back to the analogix-dp being > > the endpoint, this works exactly as expected :-) . > >=20 > > 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. > >=20 > >=20 > > 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. > >=20 > > 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. > >=20 > >=20 > > [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 n= ode > >=20 > >=20 >=20 > My previous tests were carried out on the modified RK3576 IOTEST board=20 > DTS based on RK3576 EVB1, which includes dp-connector by default. I also= =20 > did extra verification without dp-connector, and HPD detection works=20 > correctly in both cases. >=20 > I've taken a look at the Tiger board DT configuration. The pinctrl=20 > settings for the eDP HPD GPIO may need adjustment: >=20 > &pinctrl { > edp0 { > edp0_hpd_l: edp0-hpd-l-pin { > rockchip,pins =3D <4 RK_PB5 RK_FUNC_GPIO &pcfg_pull_down>; > }; > }; > }; >=20 > It is recommended to configure GPIO4B5 as pull-down or pll-none. Pull-up= =20 > configuration may prevent GPIO interrupts from being triggered properly,= =20 > resulting in a permanent "connected" status. At least on that DP-carrier the pin direction is different. I.e. it is active-low, meaning 0 for plugged in. In the schematics I do see a hw pull up too - so pull-none in the pinconfig would also be possible, but pull-down is definitly wrong on _this_ board. So we're talking about the same code, I put the dts up on [0] . I'm currently running with a printk diff [1] to showcase the issue. So on boot, with the display unplugged I get: [ 14.757911] ---> drm_bridge_connector_detect: detect [ 14.757914] ---> analogix_dp_bridge_detect a [ 14.757918] ---> drm_bridge_connector_detect: detect [ 14.773779] ---> analogix_dp_bridge_detect a [ 14.838658] rockchip-dp fdec0000.edp: failed to read dpcd caps: -110 [ 14.838662] [drm:analogix_dp_bridge_atomic_enable [analogix_dp]] *ERROR*= dp commit error, ret =3D -110 [ 14.838670] rockchip-dp fdec0000.edp: failed to set bridge, retry: 0 [ 14.884791] rockchip-dp fdec0000.edp: failed to read dpcd caps: -110 [ 14.884793] [drm:analogix_dp_bridge_atomic_enable [analogix_dp]] *ERROR*= dp commit error, ret =3D -110 [ 14.884796] rockchip-dp fdec0000.edp: failed to set bridge, retry: 1 [ 14.930925] rockchip-dp fdec0000.edp: failed to read dpcd caps: -110 [ 14.930927] [drm:analogix_dp_bridge_atomic_enable [analogix_dp]] *ERROR*= dp commit error, ret =3D -110 [ 14.930930] rockchip-dp fdec0000.edp: failed to set bridge, retry: 2 [ 14.977032] rockchip-dp fdec0000.edp: failed to read dpcd caps: -110 [ 14.977034] [drm:analogix_dp_bridge_atomic_enable [analogix_dp]] *ERROR*= dp commit error, ret =3D -110 [ 14.977037] rockchip-dp fdec0000.edp: failed to set bridge, retry: 3 [ 15.023150] rockchip-dp fdec0000.edp: failed to read dpcd caps: -110 [ 15.023152] [drm:analogix_dp_bridge_atomic_enable [analogix_dp]] *ERROR*= dp commit error, ret =3D -110 [ 15.023155] rockchip-dp fdec0000.edp: failed to set bridge, retry: 4 [ 15.023168] rockchip-dp fdec0000.edp: too many times retry set bridge, g= ive it up [ 15.052485] Console: switching to colour frame buffer device 80x30 [ 15.210457] rockchip-drm display-subsystem: [drm] fb0: rockchipdrmfb fra= me buffer device [ 15.223444] ---> drm_bridge_connector_detect: detect [ 15.231974] ---> analogix_dp_bridge_detect a [ 15.239587] ---> drm_bridge_connector_detect: detect [ 15.245341] ---> analogix_dp_bridge_detect a So analogix_dp_bridge_detect() is called and always returns connected. Plugging in the the display, I get: [ 290.592096] ---> display_connector_detect gpio value is 1 {display-con= nector returning connected} [ 290.598648] ---> drm_bridge_connector_detect: detect [ 290.604637] ---> analogix_dp_bridge_detect a [ 290.609826] ---> drm_bridge_connector_detect: detect [ 290.615784] ---> analogix_dp_bridge_detect a Unplugging the display, I get: [ 302.081444] ---> display_connector_detect gpio value is 0 {display-con= nector returning disconnected} [ 302.087996] ---> drm_bridge_connector_detect: detect [ 302.093945] ---> analogix_dp_bridge_detect a [ 302.099131] ---> drm_bridge_connector_detect: detect [ 302.105090] ---> analogix_dp_bridge_detect a [ 302.144834] ---> drm_bridge_connector_detect: detect [ 302.150784] ---> analogix_dp_bridge_detect a [ 302.155933] ---> drm_bridge_connector_detect: detect [ 302.161859] ---> analogix_dp_bridge_detect a So it looks like on the gpio-side the detection is correct and/but analogix_dp_bridge_detect() is always returning a connected state ("b" output is never reached). I'm still working on understanding how the whole detection logic works in drm ;-) . Heiko [0] https://github.com/mmind/linux-rockchip/blob/dev/v7.3/rk3588-tiger-dp-c= arrier-v5/arch/arm64/boot/dts/rockchip/rk3588-tiger-displayport-carrier.dts [1] diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/g= pu/drm/bridge/analogix/analogix_dp_core.c index 7a89548a7a885..0accdf62637ae 100644 =2D-- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -915,8 +915,10 @@ analogix_dp_bridge_detect(struct drm_bridge *bridge, s= truct drm_connector *conne struct analogix_dp_device *dp =3D to_dp(bridge); enum drm_connector_status status =3D connector_status_disconnected; =20 +printk("---> %s a\n", __func__); if (dp->plat_data->next_bridge) return connector_status_connected; +printk("---> %s b\n", __func__); =20 if (!analogix_dp_detect_hpd(dp)) status =3D connector_status_connected; diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/b= ridge/display-connector.c index 16c0631adeb18..b0c07694b82e3 100644 =2D-- a/drivers/gpu/drm/bridge/display-connector.c +++ b/drivers/gpu/drm/bridge/display-connector.c @@ -45,6 +45,7 @@ static enum drm_connector_status display_connector_detect= (struct drm_bridge *bri struct display_connector *conn =3D to_display_connector(bridge); =20 if (conn->hpd_gpio) { +printk("---> %s gpio value is %d\n", __func__, gpiod_get_value_cansleep(co= nn->hpd_gpio)); if (gpiod_get_value_cansleep(conn->hpd_gpio)) return connector_status_connected; else @@ -84,6 +85,7 @@ static enum drm_connector_status display_connector_detect= (struct drm_bridge *bri static enum drm_connector_status display_connector_bridge_detect(struct drm_bridge *bridge, struct drm_conn= ector *connector) { +printk("---> %s\n", __func__); return display_connector_detect(bridge); } =20 diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/d= rm/display/drm_bridge_connector.c index 649969fca1413..8816d837c9a77 100644 =2D-- a/drivers/gpu/drm/display/drm_bridge_connector.c +++ b/drivers/gpu/drm/display/drm_bridge_connector.c @@ -218,6 +218,7 @@ drm_bridge_connector_detect(struct drm_connector *conne= ctor, bool force) enum drm_connector_status status; =20 if (detect) { +printk("---> %s: detect\n", __func__); status =3D detect->funcs->detect(detect, connector); =20 if (hdmi)