[{"id":38342,"web_url":"https://patchwork.libcamera.org/comment/38342/","msgid":"<177279650242.1533536.2695413935031542096@ping.linuxembedded.co.uk>","date":"2026-03-06T11:28:22","subject":"Re: [PATCH v3 3/3] ipa: libipa: camera_sensor_helper: Add OV2740\n\tblack level","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Quoting Javier Tia (2026-03-05 20:10:39)\n> Set blackLevel_ = 4096 (0x40 at 10-bit) in CameraSensorHelperOv2740.\n> The OV2740 kernel driver programs BLC target register 0x4003 with 0x40\n> for the 180 MHz link frequency mode. This matches the same pattern\n> used by OV5675 and other OmniVision sensors with a 10-bit black level\n> of 64.\n> \n> Without this, the Simple pipeline falls back to auto-guessing the\n> black level, which happens to arrive at the same value but isn't\n> documented. More importantly, the CameraSensorHelper is the canonical\n> location for sensor calibration data and is used across all pipeline\n> handlers, not just Simple.\n> \n> Suggested-by: Robert Mader \n> Signed-off-by: Javier Tia \n> Reviewed-by: Milan Zamazal \n\nReviewed-by: Kieran Bingham \n\n> ---\n> src/ipa/libipa/camera_sensor_helper.cpp | 2 ++\n> 1 file changed, 2 insertions(+)\n> \n> diff --git a/src/ipa/libipa/camera_sensor_helper.cpp b/src/ipa/libipa/camera_sensor_helper.cpp\n> index e3e3e535..3028197e 100644\n> --- a/src/ipa/libipa/camera_sensor_helper.cpp\n> +++ b/src/ipa/libipa/camera_sensor_helper.cpp\n> @@ -672,6 +672,8 @@ class CameraSensorHelperOv2740 : public CameraSensorHelper\n> public:\n> CameraSensorHelperOv2740()\n> {\n> + /* From Linux kernel driver: 0x40 at 10bits. */\n> + blackLevel_ = 4096;\n> gain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n> }\n> };\n> \n> -- \n> 2.53.0\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 382CBC0DA4\n\tfor ;\n\tFri, 6 Mar 2026 11:28:28 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 63494625E5;\n\tFri, 6 Mar 2026 12:28:27 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 919C4620FA\n\tfor ;\n\tFri, 6 Mar 2026 12:28:25 +0100 (CET)","from monstersaurus.ideasonboard.com\n\t(cpc89244-aztw30-2-0-cust6594.18-1.cable.virginm.net [86.31.185.195])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 3DBD14F1;\n\tFri, 6 Mar 2026 12:27:21 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"JpY8k8s8\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1772796441;\n\tbh=aAd4Zk2rLqFfhlKCPIGs8eUhq3ReNJQdFZ0SLsJblQY=;\n\th=In-Reply-To:References:Subject:From:Cc:To:Date:From;\n\tb=JpY8k8s8ujrkpeO9VV8FSypoz6cBnxRLbQi+2uHR+GDwwfzaVC4tqS+YSlsEk6zBp\n\tpMvXoqWzBDmVm0xaOlKyqLSI4ENTgLMTcbR8w4Z6yxaJ9MRy9s098XrH7QLG1dkA95\n\tDlhfIPpjELb7/GmuqorzjCoxT6cSOarVTfQlvVf8=","Content-Type":"text/plain; charset=\"utf-8\"","MIME-Version":"1.0","Content-Transfer-Encoding":"quoted-printable","In-Reply-To":"<20260305-agc-proportional-v3-3-25abc1bfacca@jetm.me>","References":"<20260305-agc-proportional-v3-0-25abc1bfacca@jetm.me>\n\t<20260305-agc-proportional-v3-3-25abc1bfacca@jetm.me>","Subject":"Re: [PATCH v3 3/3] ipa: libipa: camera_sensor_helper: Add OV2740\n\tblack level","From":"Kieran Bingham ","Cc":"Javier Tia , Robert Mader ,\n\tMilan Zamazal ","To":"Javier Tia , libcamera-devel@lists.libcamera.org","Date":"Fri, 06 Mar 2026 11:28:22 +0000","Message-ID":"<177279650242.1533536.2695413935031542096@ping.linuxembedded.co.uk>","User-Agent":"alot/0.9.1","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]