From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-02.galae.net (smtpout-02.galae.net [185.246.84.56]) (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 477EF2E2F0E; Wed, 31 Dec 2025 10:50:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.84.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767178237; cv=none; b=DgquRv8gF6Qc3ORwceUPJxXR85gBVYkoamqe7iD52N/rmoS290+CeO9xi4vJe+OQsNdBI+APk7TCz17eGdpNbNrTKtm3LMwcPbGaY0tvTp/8Z07akG9GQ3egNZcFXAOdUiicgiiTUXXrc4s3tUuDQzv1Ed23n3lUD9H+oarwpg0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767178237; c=relaxed/simple; bh=Xx0zceu5WiAjB+oX9KeH/4JL2pr/+tcP2mxgjsJCzmg=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:To:From:Subject: References:In-Reply-To; b=QIefV+BzuFXGXEy0r8kSkW6B5OW9yDKnshfKR8Jl5mmnEikka7utS3mRC/7b/7wYrducdP4Cl3aCp5owXFDjWaXqoNoB3HVMkDHEcd2IQxChzB8siULt66yYrcsL4FmO70af2YjPZnJ6gHOkbGarfVFYwvKD9ppFJ9MvB0dgRj0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=SsqIb5ow; arc=none smtp.client-ip=185.246.84.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="SsqIb5ow" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id 85A201A255B; Wed, 31 Dec 2025 10:50:28 +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== Precedence: bulk X-Mailing-List: linux-kernel@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 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 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