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{
    "id": 19187,
    "url": "https://patchwork.libcamera.org/api/covers/19187/?format=api",
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        "name": "libcamera",
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    "msgid": "<20231102172439.3543870-1-kieran.bingham@ideasonboard.com>",
    "date": "2023-11-02T17:24:37",
    "name": "[libcamera-devel,v3,0/2] Add read-only flag to ControlInfo",
    "submitter": {
        "id": 4,
        "url": "https://patchwork.libcamera.org/api/people/4/?format=api",
        "name": "Kieran Bingham",
        "email": "kieran.bingham@ideasonboard.com"
    },
    "mbox": "https://patchwork.libcamera.org/cover/19187/mbox/",
    "series": [
        {
            "id": 4064,
            "url": "https://patchwork.libcamera.org/api/series/4064/?format=api",
            "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=4064",
            "date": "2023-11-02T17:24:37",
            "name": "Add read-only flag to ControlInfo",
            "version": 3,
            "mbox": "https://patchwork.libcamera.org/series/4064/mbox/"
        }
    ],
    "comments": "https://patchwork.libcamera.org/api/covers/19187/comments/",
    "headers": {
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        "To": "libcamera devel <libcamera-devel@lists.libcamera.org>",
        "Date": "Thu,  2 Nov 2023 17:24:37 +0000",
        "Message-Id": "<20231102172439.3543870-1-kieran.bingham@ideasonboard.com>",
        "X-Mailer": "git-send-email 2.34.1",
        "MIME-Version": "1.0",
        "Content-Transfer-Encoding": "8bit",
        "Subject": "[libcamera-devel] [PATCH v3 0/2] Add read-only flag to ControlInfo",
        "X-BeenThere": "libcamera-devel@lists.libcamera.org",
        "X-Mailman-Version": "2.1.29",
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        "List-Id": "<libcamera-devel.lists.libcamera.org>",
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        "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>",
        "From": "Kieran Bingham via libcamera-devel\n\t<libcamera-devel@lists.libcamera.org>",
        "Reply-To": "Kieran Bingham <kieran.bingham@ideasonboard.com>",
        "Errors-To": "libcamera-devel-bounces@lists.libcamera.org",
        "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>"
    },
    "content": "This small patch series adds a read-only flag to ControlInfo.  This is used\nto test if a control, in particular V4L2_CID_HBLANK, can be written to by\nuserland.  It replaces the slightly fragile workaround we have right now where\nwe test if the min and max values of a control are the same to determine if\na control is read-only.\n\nOnly modified one ControlInfo constructor is modified which is used by the\nV4L2Device class to allow this flag to be set, as setting it for a non-v4l2\ncontrol probably does not make sense at this point.\n\nModifying other ControlInfo constructors fails quite quickly falling\ninto a range of template issues due to multiple signatures matching.\n\nThe alternative here would be to rework this such that the ReadOnly flag\ncould be set /after/ construction with a setter allowing something like:\n\nV4L2_CTRL_TYPE_INTEGER64:\n \t\treturn ControlInfo(static_cast<int64_t>(ctrl.minimum),\n \t\t\t\t   static_cast<int64_t>(ctrl.maximum),\n-\t\t\t\t   static_cast<int64_t>(ctrl.default_value));\n+\t\t\t\t   static_cast<int64_t>(ctrl.default_value))\n\t\t\t\t\t.setReadOnly(ctrl.flags & V4L2_CTRL_FLAG_READ_ONLY);\n\nOf course that feels like it could remove the 'contract' of the read\nonly property by opening up the ability for a ReadOnly control to have\nthe ReadOnly flag unset - or by opening up the ability to arbitrarily\naffect a 'property' of a ControlInfo after it has been made.\n\n\nSince v2, I have made the following changes to Naush' patches:\n - Initialised ReadOnly flag as false for ControlInfo(Span<>)\n - Improved documentation\n\nNaushir Patuck (2):\n  libcamera: controls: Add read-only flag to ControlInfo\n  libcamera:camera_sensor, ipa: raspberrypi: Test readOnly() for HBLANK\n    control\n\n include/libcamera/controls.h    |  5 ++++-\n src/ipa/rpi/common/ipa_base.cpp | 12 +-----------\n src/libcamera/camera_sensor.cpp | 14 ++------------\n src/libcamera/controls.cpp      | 22 ++++++++++++++++++----\n src/libcamera/v4l2_device.cpp   | 12 ++++++++----\n 5 files changed, 33 insertions(+), 32 deletions(-)"
}