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{
    "id": 24322,
    "url": "https://patchwork.libcamera.org/api/patches/24322/?format=api",
    "web_url": "https://patchwork.libcamera.org/patch/24322/",
    "project": {
        "id": 1,
        "url": "https://patchwork.libcamera.org/api/projects/1/?format=api",
        "name": "libcamera",
        "link_name": "libcamera",
        "list_id": "libcamera_core",
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    "msgid": "<20250911135144.56586-5-mzamazal@redhat.com>",
    "date": "2025-09-11T13:51:42",
    "name": "[v2,4/6] libcamera: simple: Avoid incorrect arithmetic in AWB",
    "commit_ref": null,
    "pull_url": null,
    "state": "superseded",
    "archived": false,
    "hash": "423f58167a228128b40bbe40d5b24a79432b0892",
    "submitter": {
        "id": 177,
        "url": "https://patchwork.libcamera.org/api/people/177/?format=api",
        "name": "Milan Zamazal",
        "email": "mzamazal@redhat.com"
    },
    "delegate": null,
    "mbox": "https://patchwork.libcamera.org/patch/24322/mbox/",
    "series": [
        {
            "id": 5432,
            "url": "https://patchwork.libcamera.org/api/series/5432/?format=api",
            "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5432",
            "date": "2025-09-11T13:51:39",
            "name": "Fix stats related problems in software ISP",
            "version": 2,
            "mbox": "https://patchwork.libcamera.org/series/5432/mbox/"
        }
    ],
    "comments": "https://patchwork.libcamera.org/api/patches/24322/comments/",
    "check": "pending",
    "checks": "https://patchwork.libcamera.org/api/patches/24322/checks/",
    "tags": {},
    "headers": {
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        "X-Mimecast-MFC-AGG-ID": "rzcZWJZNOcW6Ewb-l2HE0g_1757598721",
        "From": "Milan Zamazal <mzamazal@redhat.com>",
        "To": "libcamera-devel@lists.libcamera.org",
        "Cc": "Milan Zamazal <mzamazal@redhat.com>, pobrn@protonmail.com,\n\tmail@maciej.szmigiero.name",
        "Subject": "[PATCH v2 4/6] libcamera: simple: Avoid incorrect arithmetic in AWB",
        "Date": "Thu, 11 Sep 2025 15:51:42 +0200",
        "Message-ID": "<20250911135144.56586-5-mzamazal@redhat.com>",
        "In-Reply-To": "<20250911135144.56586-1-mzamazal@redhat.com>",
        "References": "<20250911135144.56586-1-mzamazal@redhat.com>",
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        "Errors-To": "libcamera-devel-bounces@lists.libcamera.org",
        "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>"
    },
    "content": "The R/G/B sums computed in AWB simple IPA may be zero or perhaps even\nnegative.  Let's make sure the sums are always positive, to prevent\ndivision by zero or completely nonsense results.\n\nSigned-off-by: Milan Zamazal <mzamazal@redhat.com>\n---\n src/ipa/simple/algorithms/awb.cpp | 8 +++++---\n 1 file changed, 5 insertions(+), 3 deletions(-)",
    "diff": "diff --git a/src/ipa/simple/algorithms/awb.cpp b/src/ipa/simple/algorithms/awb.cpp\nindex cf567e894..9509129e9 100644\n--- a/src/ipa/simple/algorithms/awb.cpp\n+++ b/src/ipa/simple/algorithms/awb.cpp\n@@ -7,6 +7,7 @@\n \n #include \"awb.h\"\n \n+#include <algorithm>\n #include <numeric>\n #include <stdint.h>\n \n@@ -69,9 +70,10 @@ void Awb::process(IPAContext &context,\n \tconst uint64_t nPixels = std::accumulate(\n \t\thistogram.begin(), histogram.end(), 0);\n \tconst uint64_t offset = blackLevel * nPixels;\n-\tconst uint64_t sumR = stats->sumR_ - offset / 4;\n-\tconst uint64_t sumG = stats->sumG_ - offset / 2;\n-\tconst uint64_t sumB = stats->sumB_ - offset / 4;\n+\tconst uint64_t minValid = 1;\n+\tconst uint64_t sumR = std::max(stats->sumR_ - offset / 4, minValid);\n+\tconst uint64_t sumG = std::max(stats->sumG_ - offset / 2, minValid);\n+\tconst uint64_t sumB = std::max(stats->sumB_ - offset / 4, minValid);\n \n \t/*\n \t * Calculate red and blue gains for AWB.\n",
    "prefixes": [
        "v2",
        "4/6"
    ]
}