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[23.128.96.18]) by mx.google.com with ESMTP id z6si8459073ejw.244.2020.12.08.12.59.18; Tue, 08 Dec 2020 12:59:41 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=S0ie0J1A; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727998AbgLHU1a (ORCPT + 99 others); Tue, 8 Dec 2020 15:27:30 -0500 Received: from hqnvemgate25.nvidia.com ([216.228.121.64]:11790 "EHLO hqnvemgate25.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726703AbgLHU11 (ORCPT ); Tue, 8 Dec 2020 15:27:27 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Tue, 08 Dec 2020 12:26:46 -0800 Received: from [10.2.90.244] (172.20.13.39) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 8 Dec 2020 20:26:43 +0000 Subject: Re: [PATCH v3 10/13] media: v4l2-fwnode: Update V4L2_FWNODE_CSI2_MAX_DATA_LANES to 8 To: Sakari Ailus , Hans Verkuil CC: , , , , , , , , , Laurent Pinchart References: <1607022002-26575-1-git-send-email-skomatineni@nvidia.com> <1607022002-26575-11-git-send-email-skomatineni@nvidia.com> <845dfd4a-fa11-625c-78a3-cc8adc68bfc7@xs4all.nl> <20201208195949.GB1167@valkosipuli.retiisi.org.uk> From: Sowjanya Komatineni Message-ID: <23de1994-0a3e-179b-2c2f-b41917d02585@nvidia.com> Date: Tue, 8 Dec 2020 12:27:22 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201208195949.GB1167@valkosipuli.retiisi.org.uk> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1607459206; bh=V/0+9h7ehwpCJcCPaTuvyhF/G9hja/cZk0UPNoDHO74=; h=Subject:To:CC:References:From:Message-ID:Date:User-Agent: MIME-Version:In-Reply-To:Content-Type:Content-Transfer-Encoding: Content-Language:X-Originating-IP:X-ClientProxiedBy; b=S0ie0J1A5wC4XOAnEIdC/0Wl9YyUACghu0oMAax8zmeSgIDXjz049Fe24Bfch1hNF orRW/tsyQvlYk0IzXdsuQRtEWLwCrwyrNc/8MiCjcuomKAC0O+RfQZ/vHvvrswkM8n r2dngjrq9/oRiPcWa/maCNq6AFLwiVI9ImxSITsX75TYYuC95rw0PKjuWDF1OI9gIx Rri4K+0EqF2oFfCkBp4Bzv+TZmLagA8jZ9b2kuCcMIB5u6kXT+JD53ApZew5T5m98A ov3WjKl0tXYJVT/u4koi74kO8Qyzt8qRl3MagBR12ga5Fjyh3qP44PRoURp9pkTMWM 5PmCqZt6t+n+A== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/8/20 11:59 AM, Sakari Ailus wrote: > Hi Hans, > > On Mon, Dec 07, 2020 at 11:47:38AM +0100, Hans Verkuil wrote: >> On 03/12/2020 19:59, Sowjanya Komatineni wrote: >>> Some CSI2 receivers support 8 data lanes. >>> >>> So, this patch updates CSI2 maximum data lanes to be 8. >>> >>> Signed-off-by: Sowjanya Komatineni >>> --- >>> drivers/media/platform/ti-vpe/cal-camerarx.c | 2 +- >>> include/media/v4l2-fwnode.h | 2 +- >>> 2 files changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/media/platform/ti-vpe/cal-camerarx.c b/drivers/media/platform/ti-vpe/cal-camerarx.c >>> index 806cbf1..47e2143 100644 >>> --- a/drivers/media/platform/ti-vpe/cal-camerarx.c >>> +++ b/drivers/media/platform/ti-vpe/cal-camerarx.c >>> @@ -534,7 +534,7 @@ static int cal_camerarx_parse_dt(struct cal_camerarx *phy) >>> { >>> struct v4l2_fwnode_endpoint *endpoint = &phy->endpoint; >>> struct device_node *ep_node; >>> - char data_lanes[V4L2_FWNODE_CSI2_MAX_DATA_LANES * 2]; >>> + char data_lanes[V4L2_FWNODE_CSI2_MAX_DATA_LANES]; >>> unsigned int i; >>> int ret; >>> >> I'm not so sure about this change: it relies on the implicit knowledge that >> this cal driver can handle only 4 lanes max, so that doubling >> V4L2_FWNODE_CSI2_MAX_DATA_LANES is the same as the old 'V4L2_FWNODE_CSI2_MAX_DATA_LANES * 2'. >> >> I think we should either keep the existing code (which means data_lanes >> is now larger than needed, so stack usage increases by 8 bytes), or perhaps >> create a new define for this driver like CAL_MAX_DATA_LANES and use that. >> >> In my opinion the original code should just be kept, but I've CC-ed Laurent >> on this to hear what he thinks. > I further looked at the code there and it does *depend* on a particular > value of V4L2_FWNODE_CSI2_MAX_DATA_LANES. That needs to be fixed. This part > can (or should) be dropped from the patch though. > Thanks Sakari and Hans. OK. Will drop updating cal-camerarx.c from this patch in next version.