[{"id":38339,"web_url":"https://patchwork.libcamera.org/comment/38339/","msgid":"<85o6l2cci2.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","date":"2026-03-05T19:17:09","subject":"Re: [PATCH v2 4/4] ipa: libipa: camera_sensor_helper: Add OV2740\n\tblack level","submitter":{"id":177,"url":"https://patchwork.libcamera.org/api/people/177/","name":"Milan Zamazal","email":"mzamazal@redhat.com"},"content":"Javier Tia writes:\n\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\nReviewed-by: Milan Zamazal \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> \tCameraSensorHelperOv2740()\n> \t{\n> +\t\t/* From Linux kernel driver: 0x40 at 10bits. */\n> +\t\tblackLevel_ = 4096;\n> \t\tgain_ = AnalogueGainLinear{ 1, 0, 0, 128 };\n> \t}\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 CD3BAC0DA4\n\tfor ;\n\tThu, 5 Mar 2026 19:17:17 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 228E8625B1;\n\tThu, 5 Mar 2026 20:17:17 +0100 (CET)","from us-smtp-delivery-124.mimecast.com\n\t(us-smtp-delivery-124.mimecast.com [170.10.129.124])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 233E4622AE\n\tfor ;\n\tThu, 5 Mar 2026 20:17:16 +0100 (CET)","from mail-wm1-f69.google.com (mail-wm1-f69.google.com\n\t[209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS\n\t(version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id\n\tus-mta-245-x-W39CrIM4eRuXlOuBOjkg-1; Thu, 05 Mar 2026 14:17:13 -0500","by mail-wm1-f69.google.com with SMTP id\n\t5b1f17b1804b1-4837a718f41so44708005e9.2\n\tfor ;\n\tThu, 05 Mar 2026 11:17:13 -0800 (PST)","from mzamazal-thinkpadp1gen7.tpbc.csb\n\t(ip-77-48-47-2.net.vodafone.cz. 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