From patchwork Wed Mar 26 13:47:21 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Klug X-Patchwork-Id: 23056 Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id 41EADC323E for ; Wed, 26 Mar 2025 13:48:11 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id F2B4E68970; Wed, 26 Mar 2025 14:48:10 +0100 (CET) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="tnsDth5l"; dkim-atps=neutral Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 7A66468967 for ; Wed, 26 Mar 2025 14:48:06 +0100 (CET) Received: from ideasonboard.com (unknown [IPv6:2a00:6020:448c:6c00:b21a:42f4:9f3:1df6]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 95BF699F; Wed, 26 Mar 2025 14:46:18 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1742996778; bh=6luTqO35Q4YvGzgS3ENS17inTWGD0bIMd/vgI/zWHBk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tnsDth5lpBrhdxYgbFHR8lpiLMoOldlzpdElwzH0qLEXjNJBxqn6FQ+lFB2fTpZug qlrMVfnv9nHMtHHjKrhdAsHFbJZSsOUvlS8EePDLnWpGPAdo6ntf+lLSdE8R9hkrlI 14O4Md+wFIXAN3glrBZEoyfzicHZuOhzuArAFa3s= From: Stefan Klug To: libcamera-devel@lists.libcamera.org Cc: Stefan Klug , Daniel Scally Subject: [PATCH v2 2/3] ipa: libipa: agc_mean_luminance: Error out when effectiveExposureValue is zero Date: Wed, 26 Mar 2025 14:47:21 +0100 Message-ID: <20250326134727.279393-3-stefan.klug@ideasonboard.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250326134727.279393-1-stefan.klug@ideasonboard.com> References: <20250326134727.279393-1-stefan.klug@ideasonboard.com> MIME-Version: 1.0 X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" In a proper system it never happens that the effectiveExposureValue drops to zero. If that still happens due to a bug outside of agc_mean_luminance, the calculated gain goes towards infinity but the newExposureValue is still 0 because it is the result of multiplying the effectiveExposureTime with the gain, leading to wild oscillations. Catch that condition, print an error message and set the new effective exposure value to an arbitrary 10ms. Note that in any case the underlying problem must be fixed. The important change is the added error message to be able to detect such a situation. Signed-off-by: Stefan Klug Reviewed-by: Daniel Scally Reviewed-by: Laurent Pinchart --- Changes in v2: - Collected tags - Improved log message wording - Added comment on the arbitrary exposure time --- src/ipa/libipa/agc_mean_luminance.cpp | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/ipa/libipa/agc_mean_luminance.cpp b/src/ipa/libipa/agc_mean_luminance.cpp index 02555a44d271..f617fde81101 100644 --- a/src/ipa/libipa/agc_mean_luminance.cpp +++ b/src/ipa/libipa/agc_mean_luminance.cpp @@ -541,6 +541,18 @@ AgcMeanLuminance::calculateNewEv(uint32_t constraintModeIndex, std::shared_ptr exposureModeHelper = exposureModeHelpers_.at(exposureModeIndex); + if (effectiveExposureValue == 0s) { + LOG(AgcMeanLuminance, Error) + << "Effective exposure value is 0. This is a bug in AGC " + "and must be fixed for proper operation."; + /* + * Return an arbitrary exposure time > 0 to ensure regulation + * doesn't get stuck with 0 in case the sensor driver allows a + * min exposure of 0. + */ + return exposureModeHelper->splitExposure(10ms); + } + double gain = estimateInitialGain(); gain = constraintClampGain(constraintModeIndex, yHist, gain);