From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (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 09319320A31; Mon, 12 Jan 2026 09:06:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.9 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768208814; cv=none; b=A+QeinKHHM7Cz0gvEBDhxcqM7Eh3AealQ/Jpn+awH588F00oXz04v+sI9Ya1pu/TCxPFbKRZ8HtB/tObKVsZn1+t4aqyt9kObPbav0z45vpPkHEwRvUi213TJiC6DqstAiE5p3Qu0m4NR5yFRzGaLCTWtRvk9DFgicJ5fsmawh8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768208814; c=relaxed/simple; bh=YXQwUi6CbHLP0TzMIivNOpRsW/+ra/2WlhvdJDlywXA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oBDnRz9GM9UhmnIyF++DcbdGhlGAjQVgq8rrjuQSIMZ0gxjYe4Q39ZtbBTiFMM7xPVzJmZvVd6OWQ6iYuch128Ys3qSt/gDFZtCbH5ZxL12aRtmdZ/3Cq++jOSq4b1rL+bvXEQvW1uuS/6cUDs7saZe1KDr55F6AGpF9l7QoUCI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=QK+sdNAK; arc=none smtp.client-ip=198.175.65.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="QK+sdNAK" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1768208813; x=1799744813; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=YXQwUi6CbHLP0TzMIivNOpRsW/+ra/2WlhvdJDlywXA=; b=QK+sdNAKIr2N+i1XyZAlyFzOIjcQdBgqCnoaydhKgD9AWGA1Hlqv4wOH fCFDOaTI6APZpp9OEc3Af/vPgEPSITSDlC8uU5dJy3L0GjoqFntFp+9oG 00sBzU1hVKpOe/Js6fzYHWRQsZsYpoUelYBzrTxl/oXvRpmts5uckUhCg zxjJYTz8FpcmS1lM32APoamUTQSZlk2dJpygz7olNmgyIYPqujvZ8T4M7 bBpV9RiR2GPajoviX3XfMY0VYsfwQPj7Hbo0FmNrVXJgTuVNjddBZoe2h swOYRQuHSlOqDHs8mwkKaSXpCTCePRXNLKUQ3riqqZCZl6jOpKHT90VcE w==; X-CSE-ConnectionGUID: vZXfiT9xQNeAB1eTCWPq8A== X-CSE-MsgGUID: tp2c6BTAT76VLTVb0ClrLw== X-IronPort-AV: E=McAfee;i="6800,10657,11668"; a="92146485" X-IronPort-AV: E=Sophos;i="6.21,219,1763452800"; d="scan'208";a="92146485" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2026 01:06:52 -0800 X-CSE-ConnectionGUID: 8qZxiBSgT46TXyCBn6s6SQ== X-CSE-MsgGUID: mhP6ojN2QHacUb6+tklSUg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,219,1763452800"; d="scan'208";a="204058135" Received: from zzombora-mobl1 (HELO kekkonen.fi.intel.com) ([10.245.245.52]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2026 01:06:51 -0800 Received: from kekkonen.localdomain (localhost [IPv6:::1]) by kekkonen.fi.intel.com (Postfix) with SMTP id E7AB4121DC3; Mon, 12 Jan 2026 11:06:48 +0200 (EET) Date: Mon, 12 Jan 2026 11:06:48 +0200 Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo From: Sakari Ailus To: Wenmeng Liu Cc: Bryan O'Donoghue , mchehab@kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] media: i2c: imx412: wait for NVM read (T7) before programming mode registers Message-ID: References: <20260109044913.3310-1-wenmeng.liu@oss.qualcomm.com> <1344ad43-a4c4-4e37-ae4e-eddd2c577b3f@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1344ad43-a4c4-4e37-ae4e-eddd2c577b3f@oss.qualcomm.com> Hi Wenmeng, Bryan, On Mon, Jan 12, 2026 at 11:07:39AM +0800, Wenmeng Liu wrote: > > > On 1/9/2026 8:32 PM, Bryan O'Donoghue wrote: > > This delay should go at the end of the operation that requires the delay > > not at the start of the streaming operation. I would have thought that, too, but I understand there's an issue with an Arducam module. It's also not exactly clear to me if all other registers are writable at the sensor identification time or is the required delay only concerning starting streaming (I'd hope so). Also see . I haven't posted these yet, but I think it'd be useful to avoid extra delays here and elsewhere. > > > > The delay after the stream write, should be related to the stream write > > command, not the antecedent - the command that came before > > start_streaming. > > > > Basically I think you need to put your delay into the CCI_ID read NVM > > parameter load routine so that it guarantees its own completion. > > > > Because for argument's sake if start_streaming() were not to be the > > thing to happen after CCI_ID/NVM loading, the logic would no longer > > work. > > > > And you need a Fixes: tag for this patch too. > > Reading the sensor ID only occurs during the sensor probe process. After the > probe is completed, the IMX577 will power down. When stream on occurs, the > driver will power on again and then start streaming, but the sensor ID is > not read during the stream on process.I have tested this change on imx577 > modules of different models. > > So this change can only happen during power on or stream on. > > Hi Bryan, Sakari, > May I ask if you have any suggestions regarding this? Could you add a comment this delay is there for the Arducam module (and which one), that doesn't work without it? -- Kind regards, Sakari Ailus