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 704133DEAC0; Fri, 31 Jul 2026 10:30:37 +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=1785493863; cv=none; b=bcOG2tEZRfC6y05GKGveqpeBDAOEXFpA36lZUHoDnGOXAv9l+jenbJK/04KfmQzom7Uhivfkhu0oOyPlaEzAYSgL/kw/IRWVyrW79gLCb3C/JW4p6P7tqUTJZAfwi90A4a47mlJ7pnD0GnJa6ZA0/xZ5bPgWWhI4TRnodXUbO4Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785493863; c=relaxed/simple; bh=luDP0A1g6nV9PckaRs3wNVskfd++p042hrmxONvQu1g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=mPgo4UiL+0MNVWcGQ2l+JqPCB5Hba7iA6njgf0t5ycupLebskqR3tIZ6Z0GG8iyqhOgjOlw5+0HkmTnovz4EBeXtTkBJBF+5a1uJVhJo3bBwJGTVvLEIJE8KZ3i4dIxpupel1L7Mzss0tTH1i/LDc1/Mc+ROzIMLfEu+UZ2rsnE= 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=tcimYze/; 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="tcimYze/" 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=PO5HApjpuCTFoG6dK7eT7+HEMHe6ytFiN3RSifQM+mc=; b=tcimYze/jo5hh4bufcOgKeQjX0 wyD85SoNiH2b0XUX9aEL+MXU+3z+SdA36ny2eU1ECanI6IXsLOe0NBSp/aX8ISgIwU5qYagsXzEbw fEfYU99LsS4ckdkphfm6y2XOZ3Gklbu7qCKM/g5cdMl8vNJZRwydqGO7kcwjYa8XYmwA+2/zppYtO 4gJJzMXF4qEXt7gGAE1/Ia30GUClhfTMQR3f6+qJw/WdNOr9wAvic+YvSC9hPRtJQJkxrQTD7XNGd bRwsooAb0jqRs5cY7R+GK74PY92b4sQrg+naxB7RATVk7BLqA1n+CYGOnRUMSqzUEWpx9UksLSA3g WIWEA4rQ==; 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 12:30:03 +0200 Message-ID: <5209243.oAaWjsssbx@diego> In-Reply-To: <44ff5316-43cc-46be-b947-ea6e1f5da1bb@rock-chips.com> References: <20260730032744.381566-1-damon.ding@rock-chips.com> <24131962.ssLaC8jLEa@diego> <44ff5316-43cc-46be-b947-ea6e1f5da1bb@rock-chips.com> 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, 11:55:42 Mitteleurop=C3=A4ische Sommerzeit schri= eb Damon Ding: > On 7/31/2026 5:23 PM, Heiko St=C3=BCbner wrote: > > Am Freitag, 31. Juli 2026, 05:08:45 Mitteleurop=C3=A4ische Sommerzeit s= chrieb 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 Sommerz= eit 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 configuration= s. > >>>> > >>>> 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>; > >>>> }; > >>>> }; > >>>> }; > >>> > >>> 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 doe= s 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 bei= ng > >>> connected. > >>> > >>> > >>> [0] https://lore.kernel.org/linux-rockchip/20251009225050.88192-3-hei= ko@sntech.de/ > >>> ... same effect with hpd-gpios in either the edp node or dp-connector= node > >>> > >>> > >> > >> My previous tests were carried out on the modified RK3576 IOTEST board > >> DTS based on RK3576 EVB1, which includes dp-connector by default. I al= so > >> did extra verification without dp-connector, and HPD detection works > >> correctly in both cases. > >> > >> I've taken a look at the Tiger board DT configuration. The pinctrl > >> settings for the eDP HPD GPIO may need adjustment: > >> > >> &pinctrl { > >> edp0 { > >> edp0_hpd_l: edp0-hpd-l-pin { > >> rockchip,pins =3D <4 RK_PB5 RK_FUNC_GPIO &pcfg_pull_down>; > >> }; > >> }; > >> }; > >> > >> It is recommended to configure GPIO4B5 as pull-down or pll-none. Pull-= up > >> configuration may prevent GPIO interrupts from being triggered properl= y, > >> resulting in a permanent "connected" status. > >=20 > > At least on that DP-carrier the pin direction is different. > > I.e. it is active-low, meaning 0 for plugged in. > >=20 > > In the schematics I do see a hw pull up too - so pull-none in the pinco= nfig > > would also be possible, but pull-down is definitly wrong on _this_ boar= d. > >=20 > > So we're talking about the same code, I put the dts up on [0] . > >=20 > > I'm currently running with a printk diff [1] to showcase the issue. > >=20 > > 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]] *ER= ROR* 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]] *ER= ROR* 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]] *ER= ROR* 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]] *ER= ROR* 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]] *ER= ROR* 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 bridg= e, give it up > > [ 15.052485] Console: switching to colour frame buffer device 80x30 > > [ 15.210457] rockchip-drm display-subsystem: [drm] fb0: rockchipdrmfb= frame 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 > >=20 > > So analogix_dp_bridge_detect() is called and always returns connected. > >=20 > > Plugging in the the display, I get: > > [ 290.592096] ---> display_connector_detect gpio value is 1 {display= =2Dconnector 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 > >=20 > > Unplugging the display, I get: > > [ 302.081444] ---> display_connector_detect gpio value is 0 {display= =2Dconnector 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 > >=20 > >=20 > > 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). > >=20 > > I'm still working on understanding how the whole detection logic works > > in drm ;-) . > >=20 > >=20 >=20 > I think I've spotted the environmental difference between our setups. > Your DTS places the hpd-gpios property under the dp-connector node, > which is a scenario I haven't covered yet. I will reproduce and test=20 > this case locally. >=20 > As a quick experiment, could you try removing hpd-gpios from=20 > dp-connector and move it under the edp node instead? As expected, GPIO=20 > HPD should work properly with that configuration. I've updated the branch in [0] with that hpd move to the edp node, but the result is similar: With the panel _disconnected_ on boot I see [ 12.887555] ---> drm_bridge_connector_detect: detect [ 12.893104] ---> analogix_dp_bridge_detect a [ 12.897881] ---> drm_bridge_connector_detect: detect [ 12.903424] ---> analogix_dp_bridge_detect a [ 14.124848] [drm:analogix_dp_bridge_atomic_enable [analogix_dp]] *ERROR*= failed to get hpd single ret =3D -110 [ 14.124891] rockchip-dp fdec0000.edp: failed to set bridge, retry: 0 [ 14.236031] [drm:analogix_dp_bridge_atomic_enable [analogix_dp]] *ERROR*= failed to get hpd single ret =3D -110 [ 14.236074] rockchip-dp fdec0000.edp: failed to set bridge, retry: 1 [ 14.346940] [drm:analogix_dp_bridge_atomic_enable [analogix_dp]] *ERROR*= failed to get hpd single ret =3D -110 [ 14.346990] rockchip-dp fdec0000.edp: failed to set bridge, retry: 2 [ 14.458590] [drm:analogix_dp_bridge_atomic_enable [analogix_dp]] *ERROR*= failed to get hpd single ret =3D -110 [ 14.458638] rockchip-dp fdec0000.edp: failed to set bridge, retry: 3 [ 14.570262] [drm:analogix_dp_bridge_atomic_enable [analogix_dp]] *ERROR*= failed to get hpd single ret =3D -110 [ 14.570312] rockchip-dp fdec0000.edp: failed to set bridge, retry: 4 [ 14.570328] rockchip-dp fdec0000.edp: too many times retry set bridge, g= ive it up [ 14.751371] ---> drm_bridge_connector_detect: detect [ 14.757207] ---> analogix_dp_bridge_detect a So with the diff from earlier, analogix_dp_bridge_detect() still runs, finds its next bridge and returns "connected". I.e. the > > if (dp->plat_data->next_bridge) > > return connector_status_connected; part. Heiko > > [0] https://github.com/mmind/linux-rockchip/blob/dev/v7.3/rk3588-tiger-= dp-carrier-v5/arch/arm64/boot/dts/rockchip/rk3588-tiger-displayport-carrier= =2Edts > > [1] > > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drive= rs/gpu/drm/bridge/analogix/analogix_dp_core.c > > index 7a89548a7a885..0accdf62637ae 100644 > > --- 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 *bridg= e, struct drm_connector *conne > > struct analogix_dp_device *dp =3D to_dp(bridge); > > enum drm_connector_status status =3D connector_status_disconne= cted; > > =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/d= rm/bridge/display-connector.c > > index 16c0631adeb18..b0c07694b82e3 100644 > > --- 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_de= tect(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_canslee= p(conn->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_de= tect(struct drm_bridge *bri > > static enum drm_connector_status > > display_connector_bridge_detect(struct drm_bridge *bridge, struct drm= _connector *connector) > > { > > +printk("---> %s\n", __func__); > > return display_connector_detect(bridge); > > } > > =20 > > diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/g= pu/drm/display/drm_bridge_connector.c > > index 649969fca1413..8816d837c9a77 100644 > > --- 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 *c= onnector, 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) > >=20 > >=20 > >=20 > >=20 > >=20 >=20 >=20