From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69772C433F5 for ; Fri, 4 Mar 2022 18:15:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241576AbiCDSQd (ORCPT ); Fri, 4 Mar 2022 13:16:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241568AbiCDSQY (ORCPT ); Fri, 4 Mar 2022 13:16:24 -0500 Received: from mo4-p02-ob.smtp.rzone.de (mo4-p02-ob.smtp.rzone.de [85.215.255.80]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B5391C666E; Fri, 4 Mar 2022 10:15:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1646417714; s=strato-dkim-0002; d=goldelico.com; h=To:References:Message-Id:Cc:Date:In-Reply-To:From:Subject:Cc:Date: From:Subject:Sender; bh=x6yMCnO3alKHl8bvpa17cTtqDXil1QBvA/YzB+Y6Jio=; b=Rj8qbuj7YIiU0M/7SG5kKIFQ3JnK+966RzkaaLQBG2xu/pazNpn72z+oRVfT8I6Zsq XtVVcAO35auaLxXyjbYPDNZdKh2oR5/qljD5epQ0eAwp/dXOlnlj8Ti4N1mcsIQ90wNb LtLjzDYLvE5aIVWGxu/u+WUOA8471FCPRIvYXZ3y6jAD7+lsxqznahPf8eHI4dZp2EFP dfSaXqQXya4EuDZbQHOIGxA+d0fq73wWL1AVYThBQEl2sN0YrAdSe1gNAKLKs/tr/Wpc WohBJRiArrZzvI83m+iqoVjsU+TFFEHhB+jveC0MF/8GMyE7bfxpQ8c3vVZWgfO5j8iX AxHg== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":JGIXVUS7cutRB/49FwqZ7WcJeFKiMgPgp8VKxflSZ1P34KBj7gpw91N5y2S3i8QUWw==" X-RZG-CLASS-ID: mo00 Received: from imac.fritz.box by smtp.strato.de (RZmta 47.40.1 DYNA|AUTH) with ESMTPSA id n729cey24IFE7hV (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (curve X9_62_prime256v1 with 256 ECDH bits, eq. 3072 bits RSA)) (Client did not present a certificate); Fri, 4 Mar 2022 19:15:14 +0100 (CET) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.21\)) Subject: Re: [Letux-kernel] [PATCH v16 1/4] drm/bridge: dw-hdmi: introduce dw_hdmi_enable_poll() From: "H. Nikolaus Schaller" In-Reply-To: <8JF88R.9V5YQ3Q6E8QO2@crapouillou.net> Date: Fri, 4 Mar 2022 19:15:13 +0100 Cc: Neil Armstrong , Paul Boddie , Andrzej Hajda , Maxime Ripard , Jonas Karlman , David Airlie , Robert Foss , linux-mips , dri-devel , linux-kernel , Kieran Bingham , Jernej Skrabec , Discussions about the Letux Kernel , Laurent Pinchart Content-Transfer-Encoding: quoted-printable Message-Id: <5CC8B441-AA50-45F5-A5D3-2F40F72A1B50@goldelico.com> References: <983e9064-17ad-e646-f37d-ca9173ba0967@baylibre.com> <3E620AF4-402E-45EA-9D92-92EAEA9647F5@goldelico.com> <929BF693-D54F-40F0-BB61-520301D1C31F@goldelico.com> <8JF88R.9V5YQ3Q6E8QO2@crapouillou.net> To: Paul Cercueil X-Mailer: Apple Mail (2.3445.104.21) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Paul, > Am 04.03.2022 um 19:04 schrieb Paul Cercueil : >=20 >=20 >=20 > Le ven., mars 4 2022 at 18:51:14 +0100, H. Nikolaus Schaller = a =C3=A9crit : >> Hi Paul, Neil, >>> Am 04.03.2022 um 17:47 schrieb Paul Cercueil : >>> =46rom what I understood in Nikolaus' last message, HDMI hotplug is = actually correctly detected, so there's no need for polling. What is = missing is the call to drm_kms_helper_hotplug_event *somewhere*, so that = the information is correctly relayed to userspace. >> Exactly. >> As Maxime pointed out it should already be called by = drm_helper_hpd_irq_event() in dw_hdmi_irq() but isn't >> because mode_config.poll_enabled isn't enabled. >> So we can either >> a) enable mode_config.poll_enabled so that it is called by = drm_helper_hpd_irq_event() or >> b) make drm_kms_helper_hotplug_event() being called explicitly in = dw_hdmi_irq(). >> We could guard that by mode_config.poll_enabled to avoid = drm_kms_helper_hotplug_event() >> being called twice (but I think the "changed" mechanism will take = care of). >>> I think this issue can be fixed by calling = drm_bridge_connector_enable_hpd() on the connector in ingenic-drm-drv.c. >> I don't see yet how this would solve it, but it may work. >=20 > dw_hdmi_irq() calls drm_bridge_hpd_notify(), which would call = bridge->hpd_cb() if it was non-NULL. Ok, this is a case c). I vaguely remember having tried to analyse what bridge->hpd_cb is but = stopped since it is NULL... >=20 > Calling drm_bridge_connector_enable_hpd() will set the = bridge->hpd_cb() callback to point to drm_bridge_connector_hpd_cb(), = which itself will call drm_kms_helper_hotplug_event(). Therefore, all = that is missing is one call to drm_bridge_connector_enable_hpd(). Ah, ok, I see. >> Anyways, this all is a missing feature (sometimes called "bug") of = the *dw-hdmi driver* and IMHO >> neither of the connector nor the ingenic-drm-drv. Well, a little more analysis shows that drm_bridge_connector_enable_hpd = is called in the *-drv.c for some other plaforms: = https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/imx/dcss/dc= ss-dev.c#L292 = https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/imx/dcss/dc= ss-kms.c#L145 = https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/omapdrm/oma= p_drv.c#L393 = https://elixir.bootlin.com/linux/v5.17-rc6/source/drivers/gpu/drm/msm/hdmi= /hdmi.c#L317 >> So I think it should not be solved outside dw-hdmi. Hm. Can we call drm_bridge_connector_enable_hpd() from inside dw-hdmi? Or would this be the solution if merged? (I currently can't try code). = https://lore.kernel.org/lkml/a7d0b013-6114-07b3-0a7b-0d17db8a3982@cogentem= bedded.com/T/ BR and thanks, Nikolaus From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 94F1CC433F5 for ; Fri, 4 Mar 2022 18:15:36 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AA5A5112E56; Fri, 4 Mar 2022 18:15:35 +0000 (UTC) Received: from mo4-p02-ob.smtp.rzone.de (mo4-p02-ob.smtp.rzone.de [85.215.255.80]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2A688112E56 for ; Fri, 4 Mar 2022 18:15:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1646417714; s=strato-dkim-0002; d=goldelico.com; h=To:References:Message-Id:Cc:Date:In-Reply-To:From:Subject:Cc:Date: From:Subject:Sender; bh=x6yMCnO3alKHl8bvpa17cTtqDXil1QBvA/YzB+Y6Jio=; b=Rj8qbuj7YIiU0M/7SG5kKIFQ3JnK+966RzkaaLQBG2xu/pazNpn72z+oRVfT8I6Zsq XtVVcAO35auaLxXyjbYPDNZdKh2oR5/qljD5epQ0eAwp/dXOlnlj8Ti4N1mcsIQ90wNb LtLjzDYLvE5aIVWGxu/u+WUOA8471FCPRIvYXZ3y6jAD7+lsxqznahPf8eHI4dZp2EFP dfSaXqQXya4EuDZbQHOIGxA+d0fq73wWL1AVYThBQEl2sN0YrAdSe1gNAKLKs/tr/Wpc WohBJRiArrZzvI83m+iqoVjsU+TFFEHhB+jveC0MF/8GMyE7bfxpQ8c3vVZWgfO5j8iX AxHg== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":JGIXVUS7cutRB/49FwqZ7WcJeFKiMgPgp8VKxflSZ1P34KBj7gpw91N5y2S3i8QUWw==" X-RZG-CLASS-ID: mo00 Received: from imac.fritz.box by smtp.strato.de (RZmta 47.40.1 DYNA|AUTH) with ESMTPSA id n729cey24IFE7hV (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (curve X9_62_prime256v1 with 256 ECDH bits, eq. 3072 bits RSA)) (Client did not present a certificate); Fri, 4 Mar 2022 19:15:14 +0100 (CET) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.21\)) Subject: Re: [Letux-kernel] [PATCH v16 1/4] drm/bridge: dw-hdmi: introduce dw_hdmi_enable_poll() From: "H. Nikolaus Schaller" In-Reply-To: <8JF88R.9V5YQ3Q6E8QO2@crapouillou.net> Date: Fri, 4 Mar 2022 19:15:13 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: <5CC8B441-AA50-45F5-A5D3-2F40F72A1B50@goldelico.com> References: <983e9064-17ad-e646-f37d-ca9173ba0967@baylibre.com> <3E620AF4-402E-45EA-9D92-92EAEA9647F5@goldelico.com> <929BF693-D54F-40F0-BB61-520301D1C31F@goldelico.com> <8JF88R.9V5YQ3Q6E8QO2@crapouillou.net> To: Paul Cercueil X-Mailer: Apple Mail (2.3445.104.21) X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Boddie , Jonas Karlman , David Airlie , dri-devel , Neil Armstrong , linux-mips , Robert Foss , linux-kernel , Kieran Bingham , Maxime Ripard , Andrzej Hajda , Discussions about the Letux Kernel , Jernej Skrabec , Laurent Pinchart Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Paul, > Am 04.03.2022 um 19:04 schrieb Paul Cercueil : >=20 >=20 >=20 > Le ven., mars 4 2022 at 18:51:14 +0100, H. Nikolaus Schaller = a =C3=A9crit : >> Hi Paul, Neil, >>> Am 04.03.2022 um 17:47 schrieb Paul Cercueil : >>> =46rom what I understood in Nikolaus' last message, HDMI hotplug is = actually correctly detected, so there's no need for polling. What is = missing is the call to drm_kms_helper_hotplug_event *somewhere*, so that = the information is correctly relayed to userspace. >> Exactly. >> As Maxime pointed out it should already be called by = drm_helper_hpd_irq_event() in dw_hdmi_irq() but isn't >> because mode_config.poll_enabled isn't enabled. >> So we can either >> a) enable mode_config.poll_enabled so that it is called by = drm_helper_hpd_irq_event() or >> b) make drm_kms_helper_hotplug_event() being called explicitly in = dw_hdmi_irq(). >> We could guard that by mode_config.poll_enabled to avoid = drm_kms_helper_hotplug_event() >> being called twice (but I think the "changed" mechanism will take = care of). >>> I think this issue can be fixed by calling = drm_bridge_connector_enable_hpd() on the connector in ingenic-drm-drv.c. >> I don't see yet how this would solve it, but it may work. >=20 > dw_hdmi_irq() calls drm_bridge_hpd_notify(), which would call = bridge->hpd_cb() if it was non-NULL. Ok, this is a case c). I vaguely remember having tried to analyse what bridge->hpd_cb is but = stopped since it is NULL... >=20 > Calling drm_bridge_connector_enable_hpd() will set the = bridge->hpd_cb() callback to point to drm_bridge_connector_hpd_cb(), = which itself will call drm_kms_helper_hotplug_event(). Therefore, all = that is missing is one call to drm_bridge_connector_enable_hpd(). Ah, ok, I see. >> Anyways, this all is a missing feature (sometimes called "bug") of = the *dw-hdmi driver* and IMHO >> neither of the connector nor the ingenic-drm-drv. Well, a little more analysis shows that drm_bridge_connector_enable_hpd = is called in the *-drv.c for some other plaforms: = https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/imx/dcss/dc= ss-dev.c#L292 = https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/imx/dcss/dc= ss-kms.c#L145 = https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/omapdrm/oma= p_drv.c#L393 = https://elixir.bootlin.com/linux/v5.17-rc6/source/drivers/gpu/drm/msm/hdmi= /hdmi.c#L317 >> So I think it should not be solved outside dw-hdmi. Hm. Can we call drm_bridge_connector_enable_hpd() from inside dw-hdmi? Or would this be the solution if merged? (I currently can't try code). = https://lore.kernel.org/lkml/a7d0b013-6114-07b3-0a7b-0d17db8a3982@cogentem= bedded.com/T/ BR and thanks, Nikolaus