From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout1.w1.samsung.com (mailout1.w1.samsung.com [210.118.77.11]) (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 50BAA4A1E for ; Thu, 12 Jun 2025 06:31:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.118.77.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749709883; cv=none; b=c9tVLbyjgvXfAmIbqEXXRpO3Aq60XelA24vNWVzr5PD3GmW2e1MreO3n3/arkWTQyRfdCELCqV65l1bTzr1pgKPJLYJ8B0Rhd1DF2hCF2+Mu0oaVDKKaEt+HzNaxKBu5vsoFHQfN15xHJMyMbzKSC1RD7cZj0RhXbxys0GGHKCk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749709883; c=relaxed/simple; bh=EHVk04Bu95fbP8u/8uD/BqwoW421L/Z/lwsYM/L7h4s=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:From:In-Reply-To: Content-Type:References; b=PFeMH7HGWF5N+uklyvm5E2PjYVHnzyBq0Oic+0DMcXhkdpBVtXIeBRK1zXenps6UiPulY/jNGiKO5MEuOFIE5fsv2GkLa7SXqzSSMKqGjBOkhrtycCRFCN1h3EncGb5BAjFCRBGz1YSKTd+FDG6zPd1RzYn8tHdKdoij6VgmYdU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=N8KQDHCn; arc=none smtp.client-ip=210.118.77.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="N8KQDHCn" Received: from eucas1p1.samsung.com (unknown [182.198.249.206]) by mailout1.w1.samsung.com (KnoxPortal) with ESMTP id 20250612063116euoutp016a1fbd977fcda5941b26f2057646b6a6~IN9yzdcxl0364003640euoutp01q for ; Thu, 12 Jun 2025 06:31:16 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20250612063116euoutp016a1fbd977fcda5941b26f2057646b6a6~IN9yzdcxl0364003640euoutp01q DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1749709876; bh=Ew/g1UXz/hgtaNGOb7IBVUe+5gqN+QBu6fGNGxtxMcM=; h=Date:Subject:To:Cc:From:In-Reply-To:References:From; b=N8KQDHCnqvKPlHmfzrZaajutrgDSMXcvnfGd+tx7QjtDpnnzyc36jRmd5unCE15w7 SXB1V7kkhWrXeKc0Bbr15HPuEX8ddBvzDudy5+2SiipMDJvlA1p8EqfVVH9KrggMWK uPysBGRm1/FmIHuCdKbbP9aJezWBB/Q7Oa6Z16x0= Received: from eusmtip2.samsung.com (unknown [203.254.199.222]) by eucas1p2.samsung.com (KnoxPortal) with ESMTPA id 20250612063115eucas1p274f42f875c2ee8bfbb082da420e9b9e2~IN9yIk3KQ2436824368eucas1p2L; Thu, 12 Jun 2025 06:31:15 +0000 (GMT) Received: from [106.210.134.192] (unknown [106.210.134.192]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20250612063113eusmtip2c2e86e68dc5a8d2b82f468816bdb3d44~IN9wQgs2H1607016070eusmtip2W; Thu, 12 Jun 2025 06:31:13 +0000 (GMT) Message-ID: Date: Thu, 12 Jun 2025 08:31:12 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v13 3/4] drm/atomic-helper: Re-order bridge chain pre-enable and post-disable To: Tomi Valkeinen , Aradhya Bhatia Cc: DRI Development List , Linux Kernel List , Nishanth Menon , Vignesh Raghavendra , Devarsh Thakkar , Jayesh Choudhary , Alexander Sverdlin , Dmitry Baryshkov , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter Content-Language: en-US From: Marek Szyprowski In-Reply-To: <306f142f-f9c9-44ab-a5b9-c71db76b2b80@ideasonboard.com> Content-Transfer-Encoding: 7bit X-CMS-MailID: 20250612063115eucas1p274f42f875c2ee8bfbb082da420e9b9e2 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20250611104512eucas1p22450fccf3bb7521760bd2d9a2a56ba19 X-EPHeader: CA X-CMS-RootMailID: 20250611104512eucas1p22450fccf3bb7521760bd2d9a2a56ba19 References: <20250605171524.27222-1-aradhya.bhatia@linux.dev> <20250605171524.27222-4-aradhya.bhatia@linux.dev> <2c51cf39-13cb-413f-8dd5-53bc1c11467a@samsung.com> <306f142f-f9c9-44ab-a5b9-c71db76b2b80@ideasonboard.com> On 12.06.2025 07:49, Tomi Valkeinen wrote: > On 11/06/2025 13:45, Marek Szyprowski wrote: >> On 05.06.2025 19:15, Aradhya Bhatia wrote: >>> From: Aradhya Bhatia >>> >>> Move the bridge pre_enable call before crtc enable, and the bridge >>> post_disable call after the crtc disable. >>> >>> The sequence of enable after this patch will look like: >>> >>> bridge[n]_pre_enable >>> ... >>> bridge[1]_pre_enable >>> >>> crtc_enable >>> encoder_enable >>> >>> bridge[1]_enable >>> ... >>> bridge[n]_enable >>> >>> And, the disable sequence for the display pipeline will look like: >>> >>> bridge[n]_disable >>> ... >>> bridge[1]_disable >>> >>> encoder_disable >>> crtc_disable >>> >>> bridge[1]_post_disable >>> ... >>> bridge[n]_post_disable >>> >>> The definition of bridge pre_enable hook says that, >>> "The display pipe (i.e. clocks and timing signals) feeding this bridge >>> will not yet be running when this callback is called". >>> >>> Since CRTC is also a source feeding the bridge, it should not be enabled >>> before the bridges in the pipeline are pre_enabled. Fix that by >>> re-ordering the sequence of bridge pre_enable and bridge post_disable. >>> >>> While at it, update the drm bridge API documentation as well. >>> >>> Acked-by: Dmitry Baryshkov >>> Reviewed-by: Tomi Valkeinen >>> Reviewed-by: Thomas Zimmermann >>> Tested-by: Tomi Valkeinen >>> Tested-by: Alexander Sverdlin >>> Signed-off-by: Aradhya Bhatia >>> Signed-off-by: Aradhya Bhatia >> This patch landed in today's linux-next as commit c9b1150a68d9 >> ("drm/atomic-helper: Re-order bridge chain pre-enable and >> post-disable"). In my tests I found that it breaks booting of Samsung >> Exynos 5420/5800 based Chromebooks (Peach-Pit and Peach-Pi). Both of >> them use Exynos DRM with Exynos_DP sub-driver (Analogix DP) and EDP >> panel. Booting stops at '[drm] Initialized exynos 1.1.0 for exynos-drm >> on minor 0' message. On the other hand, the Samsung Exynos5250 based >> Snow Chromebook boots fine, but it uses dp-lvds nxp,ptn3460 bridge and >> lvds panel instead of edp panels. This looks like some sort of deadlock, >> because if I disable FBDEV emulation, those boards boots fine and I'm >> able to run modetest and enable the display. Also the DRM kernel logger >> seems to be working fine, although I didn't check the screen output yet, >> as I only have a remote access to those boards. I will investigate it >> further and let You know. > Thanks for the report. I was trying to understand the pipeline, but I'm > a bit confused. Above you say Peach-Pit uses DP and EDP panel, but if I > look at arch/arm/boot/dts/samsung/exynos5420-peach-pit.dts, it connects > a dp->lvds bridge (parade,ps8625). Peach-Pi seems to connect to an eDP > panel. > > Is the above correct? Do both Peach-Pi and Peach-Pit fail? Yes, sorry, my fault. I much have checked the same (peach-pi) dts 2 times. Both Peach-Pi and Peach-Pit fails, while Snow works fine. All three use the same Exynos DP (based on analogix dp) driver. I will try to play a bit more with those boards in the afternoon, hopefully getting some more hints where the issue is. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland