[{"id":38170,"web_url":"https://patchwork.libcamera.org/comment/38170/","msgid":"<2a275fb1-ac57-4338-9ff4-4d0b6eb81705@linaro.org>","date":"2026-02-11T13:26:49","subject":"Re: [PATCH 1/2] ipa: simple: Limit the black level value","submitter":{"id":175,"url":"https://patchwork.libcamera.org/api/people/175/","name":"Bryan O'Donoghue","email":"bryan.odonoghue@linaro.org"},"content":"On 11/02/2026 13:17, Milan Zamazal wrote:\n> The black level value is passed to image processing, where it's used in\n> pixel value computations. To avoid troubles with weird black level\n> values (which are mostly theoretical but we should be still safe against\n> e.g. crazy values in testing tuning files) like division by zero, let's\n> make sure the black level passed to the image processing is lower than\n> the maximum pixel value.\n> \n> Signed-off-by: Milan Zamazal \n> ---\n> src/ipa/simple/algorithms/blc.cpp | 7 ++++---\n> 1 file changed, 4 insertions(+), 3 deletions(-)\n> \n> diff --git a/src/ipa/simple/algorithms/blc.cpp b/src/ipa/simple/algorithms/blc.cpp\n> index 464e43c27..b318d0354 100644\n> --- a/src/ipa/simple/algorithms/blc.cpp\n> +++ b/src/ipa/simple/algorithms/blc.cpp\n> @@ -1,6 +1,6 @@\n> /* SPDX-License-Identifier: LGPL-2.1-or-later */\n> /*\n> - * Copyright (C) 2024-2025, Red Hat Inc.\n> + * Copyright (C) 2024-2026, Red Hat Inc.\n> *\n> * Black level handling\n> */\n> @@ -52,8 +52,9 @@ void BlackLevel::prepare(IPAContext &context,\n> \t\t\t [[maybe_unused]] IPAFrameContext &frameContext,\n> \t\t\t DebayerParams *params)\n> {\n> -\t/* Latch the blacklevel gain so GPUISP can apply. */\n> -\tparams->blackLevel = RGB(context.activeState.blc.level / 255.0f);\n> +\t/* Make sure the black level is sane, i.e. below maximum pixel value. */\n> +\tparams->blackLevel = RGB(context.activeState.blc.level / 255.0f)\n> +\t\t\t\t .min(0.99);\n> }\n> \n> void BlackLevel::process(IPAContext &context,\nReviewed-by: Bryan O'Donoghue ","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 CE6E2BD78E\n\tfor ;\n\tWed, 11 Feb 2026 13:26:55 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 2D42B621AB;\n\tWed, 11 Feb 2026 14:26:55 +0100 (CET)","from mail-wr1-x429.google.com (mail-wr1-x429.google.com\n\t[IPv6:2a00:1450:4864:20::429])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 1FC77620C9\n\tfor ;\n\tWed, 11 Feb 2026 14:26:53 +0100 (CET)","by mail-wr1-x429.google.com with SMTP id\n\tffacd0b85a97d-4362507f396so1734290f8f.0\n\tfor ;\n\tWed, 11 Feb 2026 05:26:53 -0800 (PST)","from [192.168.0.40] (188-141-3-146.dynamic.upc.ie. 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