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{ "id": 24533, "url": "https://patchwork.libcamera.org/api/1.1/covers/24533/?format=api", "web_url": "https://patchwork.libcamera.org/cover/24533/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/1.1/projects/1/?format=api", "name": "libcamera", "link_name": "libcamera", "list_id": "libcamera_core", "list_email": "libcamera-devel@lists.libcamera.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20250930150428.11101-1-hansg@kernel.org>", "date": "2025-09-30T15:04:22", "name": "[v4,0/6] ipa: software_isp: AGC: Fix AGC oscillation bug", "submitter": { "id": 239, "url": "https://patchwork.libcamera.org/api/1.1/people/239/?format=api", "name": "Hans de Goede", "email": "hansg@kernel.org" }, "mbox": "https://patchwork.libcamera.org/cover/24533/mbox/", "series": [ { "id": 5470, "url": "https://patchwork.libcamera.org/api/1.1/series/5470/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5470", "date": "2025-09-30T15:04:22", "name": "ipa: software_isp: AGC: Fix AGC oscillation bug", "version": 4, "mbox": "https://patchwork.libcamera.org/series/5470/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/covers/24533/comments/", "headers": { "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>", "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 72769C328C\n\tfor <parsemail@patchwork.libcamera.org>;\n\tTue, 30 Sep 2025 15:04:37 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id EF8836B5F0;\n\tTue, 30 Sep 2025 17:04:35 +0200 (CEST)", "from tor.source.kernel.org (tor.source.kernel.org\n\t[IPv6:2600:3c04:e001:324:0:1991:8:25])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 197EE62C35\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tTue, 30 Sep 2025 17:04:34 +0200 (CEST)", "from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58])\n\tby tor.source.kernel.org (Postfix) with ESMTP id C0EAA62392\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tTue, 30 Sep 2025 15:04:32 +0000 (UTC)", "by smtp.kernel.org (Postfix) with ESMTPSA id AA774C116C6;\n\tTue, 30 Sep 2025 15:04:31 +0000 (UTC)" ], "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (2048-bit key;\n\tunprotected) header.d=kernel.org header.i=@kernel.org\n\theader.b=\"aITFf9wQ\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n\ts=k20201202; t=1759244672;\n\tbh=JtmL/i/cz9TgKfkCs1cXAc2A0qBkCFiQHQcJTWvKDpE=;\n\th=From:To:Cc:Subject:Date:From;\n\tb=aITFf9wQhv15QTg7BIRqY7uBbJZjXvVuINvoyVghXW1FDH2d6GKoBkkhPBHPnl9PE\n\tsTubgMY0ffnIAUxXBAnBQezvW/YZkUdVJk5cNdc6Y80Tt+qI812A3MjwELV72ALop6\n\tYfJTXRdeH1Ql+g3zfwjQs6tuaUR60qpdmbiAfsda69GG8NhG1HNByfSaGwpf2WMsfu\n\tLS4eNXbKJ+8KL+pSqfsRuSAWcYBCvaNsO8Zdrv1NcmRMC1pQf4o+u5Yh0tjZ0gEECx\n\tlRE3xr4ChRo/B97I1A4u6MzUnZpYySAgweYCPDXNYZaJW5ImnECzKigfSZ+cAeLgTS\n\txLcZky9alh3NQ==", "From": "Hans de Goede <hansg@kernel.org>", "To": "libcamera-devel@lists.libcamera.org", "Cc": "Hans de Goede <hansg@kernel.org>", "Subject": "[PATCH v4 0/6] ipa: software_isp: AGC: Fix AGC oscillation bug", "Date": "Tue, 30 Sep 2025 17:04:22 +0200", "Message-ID": "<20250930150428.11101-1-hansg@kernel.org>", "X-Mailer": "git-send-email 2.51.0", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-BeenThere": "libcamera-devel@lists.libcamera.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "Errors-To": "libcamera-devel-bounces@lists.libcamera.org", "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>" }, "content": "Hi All,\n\nDue to a combination of not having correct control-delay information for\nvarious sensors as well as the generic nature of the simple-pipeline +\nsoftware-ISP meaning that any pipeline delays are unknown it is impossible\nto get reliable control-delay values.\n\nWrong control-delay values can lead to pretty bad oscilation. See the v1\ncover-letter for more details.\n\nThis series fixes some unrelated issues in the softIPA AGC algorithm and\nin the last 2 patches addresses the oscillation issue. Note v2 and later\ntake a new approach to fixing the oscilation by only generating statistics\nfor every 4th frame and having the IPA only run its algorithms when there\nactually are statistics. This saves CPU time, while at the same time\navoiding the oscillation issue.\n\nv4 has successfully passed CI, see:\nhttps://gitlab.freedesktop.org/camera/libcamera-softisp/-/commit/e749d265ff6ec85752198dc1ab23ef2a42ab36af/pipelines?ref=softisp-agc-oscillation-fixes-v4\n\nChanges in v4:\n- AGC: Add an empty line after the agc substruct declaration\n- AGC: Init active-state agc gain and exposue from sensor values in case\n updateExposure() does not run for the first frame\n- SwStats: Document why to skip 3 frames / why once every 4 frames\n- Pass frame number to SwStatsCpu::startFrame() SwStatsCpu::processLine?()\n and move all skipping handling to inside the SwStatsCpu class\n\nChanges in v3:\n- Drop if (!stats_->valid) early exit from IPASoftSimple::processStats()\n- Save last AGC calculated new gain and exposure values and re-use these\n for frames without statistics, this avoids delayedCtrl history underruns\n- Improve SwIspStats.valid documentation\n\nChanges in v2:\n- Skip running IPA algorithms when there are no statistics\n- Only generate statistics for every 4th frame\n\nNote the speed of the AGC algorithm converges on the desired brightness\nlevel is unchanged compared to v1 since in v1 the AGC algorithm would\nskip 3 frames after every gain/exposure change.\n\nRegards,\n\nHans\n\n\nHans de Goede (6):\n ipa: software_isp: Fix context_.configuration.agc.againMin init\n ipa: software_isp: AGC: Do not lower gain below 1.0\n ipa: software_isp: AGC: Raise exposure or gain not both at the same\n time\n ipa: software_isp: AGC: Only use integers for exposure calculations\n libcamera: software_isp: Add valid flag to struct SwIspStats\n libcamera: software_isp: Run sw-statistics once every 4th frame\n\n .../internal/software_isp/swisp_stats.h | 5 ++\n src/ipa/simple/algorithms/agc.cpp | 47 ++++++++++++++-----\n src/ipa/simple/algorithms/awb.cpp | 3 ++\n src/ipa/simple/algorithms/blc.cpp | 3 ++\n src/ipa/simple/ipa_context.h | 7 ++-\n src/ipa/simple/soft_simple.cpp | 7 ++-\n src/libcamera/software_isp/debayer_cpu.cpp | 18 +++----\n src/libcamera/software_isp/debayer_cpu.h | 4 +-\n src/libcamera/software_isp/swstats_cpu.cpp | 18 +++++--\n src/libcamera/software_isp/swstats_cpu.h | 20 ++++++--\n 10 files changed, 100 insertions(+), 32 deletions(-)" }