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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 6C175EE6427 for ; Wed, 31 Dec 2025 10:50:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:References: Subject:From:To:Cc:Message-Id:Date:Content-Type:Content-Transfer-Encoding: Mime-Version:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=o/Z1oWMJuqMZIoKFGfzInyQtaixm68ScowVMHojeTZ4=; b=u/w2Kr0a3sc54mfb9ZNBlnklCM drwJct+EpjiLm5QPUszd5AveuGdT1Gkv9YiKl1Si3gmQyVQHg6DcwoqGdaMYkBpea3lqUIGzOb95x UQ+c3f4JLfWQ6elWJFwi8pBC/jksO4c351CEZZuJMBYPcOIT+d7JDt/Gj3WIWqfuS4B0zAq3e4lsY wH56vD1gcIg4oRiP2kFE568rK0Z0dwhty15R342WGyK/Tjp64J/WJcz9yJUAUm4lWu9vbtDYb+3WU l+oS5EFCjRen7H76jK10HbHZoBO+fHTe2OUNPGhnDiONeXAW42XyDPHPiQKkpG2eLWguanYohwCHz v/MenQ8w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vatmn-00000005tkM-0sIp; Wed, 31 Dec 2025 10:50:37 +0000 Received: from smtpout-04.galae.net ([185.171.202.116]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vatmj-00000005tjy-1WJg; Wed, 31 Dec 2025 10:50:35 +0000 Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-04.galae.net (Postfix) with ESMTPS id D2CD4C1AE22; Wed, 31 Dec 2025 10:50:02 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 4A06060744; Wed, 31 Dec 2025 10:50:28 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 52745113B0761; Wed, 31 Dec 2025 11:50:16 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1767178226; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=o/Z1oWMJuqMZIoKFGfzInyQtaixm68ScowVMHojeTZ4=; b=SsqIb5ow7v/6UFYF34MR3rDUSBx3YczuZw7xKUxdk+tgkyoQgTiXQNv11eRgnwbhpuarKw UeIQgJ1dioQ7o1MXOWuHqmtVIrpWKfvK5sqXw8geFXGwRo1gINFkN+RfKVIvRjG+HRbFNT 7RVR5xnIwrJ9zLALAGWwVBqa72bYwfYaH/9s8czYbZ8C97aQMKiEXHKI1WcGf1tsxNi6AW h3tACyEXkQgbWLG61NjtwwWBjENblxG4eY2cmCq9ed9jeUVexoG931bT7Cx9Xt+UXBZdV1 d7+IE+kBV+JgFf93zyVPI/DpCiIdUX2tl4nMm0jVJT1oXZ700jLDDOVoRCqavw== Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 31 Dec 2025 11:50:15 +0100 Message-Id: Cc: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , To: "Damon Ding" , , , From: "Luca Ceresoli" Subject: Re: [PATCH v8 01/18] drm/display: bridge_connector: Ensure last bridge determines EDID/modes detection capabilities X-Mailer: aerc 0.20.1 References: <20251217093321.3108939-1-damon.ding@rock-chips.com> <20251217093321.3108939-2-damon.ding@rock-chips.com> In-Reply-To: <20251217093321.3108939-2-damon.ding@rock-chips.com> X-Last-TLS-Session-Version: TLSv1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251231_025033_560775_36076D5C X-CRM114-Status: UNSURE ( 9.56 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed Dec 17, 2025 at 10:33 AM CET, Damon Ding wrote: > When multiple bridges are present, EDID detection capability > (DRM_BRIDGE_OP_EDID) takes precedence over modes detection > (DRM_BRIDGE_OP_MODES). To ensure the above two capabilities are > determined by the last bridge in the chain, we handle three cases: > > Case 1: The later bridge declares only DRM_BRIDGE_OP_MODES > - If the previous bridge declares DRM_BRIDGE_OP_EDID, set > &drm_bridge_connector.bridge_edid to NULL and set > &drm_bridge_connector.bridge_modes to the later bridge. > - Ensure modes detection capability of the later bridge will not > be ignored. > > Case 2: The later bridge declares only DRM_BRIDGE_OP_EDID > - If the previous bridge declares DRM_BRIDGE_OP_MODES, set > &drm_bridge_connector.bridge_modes to NULL and set > &drm_bridge_connector.bridge_edid to the later bridge. > - Although EDID detection capability has higher priority, this > operation is for balance and makes sense. > > Case 3: the later bridge declares both of them > - Assign later bridge as &drm_bridge_connector.bridge_edid and > and &drm_bridge_connector.bridge_modes to this bridge. > - Just leave transfer of these two capabilities as before. > > Signed-off-by: Damon Ding > Suggested-by: Dmitry Baryshkov > Tested-by: Marek Szyprowski Reviewed-by: Luca Ceresoli -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com