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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
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treea94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/userspace-api/media/mediactl/media-ioc-device-info.rst
parentInitial commit. (diff)
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Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
+
+.. _media_ioc_device_info:
+
+***************************
+ioctl MEDIA_IOC_DEVICE_INFO
+***************************
+
+Name
+====
+
+MEDIA_IOC_DEVICE_INFO - Query device information
+
+Synopsis
+========
+
+.. c:macro:: MEDIA_IOC_DEVICE_INFO
+
+``int ioctl(int fd, MEDIA_IOC_DEVICE_INFO, struct media_device_info *argp)``
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by :c:func:`open()`.
+
+``argp``
+ Pointer to struct :c:type:`media_device_info`.
+
+Description
+===========
+
+All media devices must support the ``MEDIA_IOC_DEVICE_INFO`` ioctl. To
+query device information, applications call the ioctl with a pointer to
+a struct :c:type:`media_device_info`. The driver
+fills the structure and returns the information to the application. The
+ioctl never fails.
+
+.. c:type:: media_device_info
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. flat-table:: struct media_device_info
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 1 2
+
+ * - char
+ - ``driver``\ [16]
+ - Name of the driver implementing the media API as a NUL-terminated
+ ASCII string. The driver version is stored in the
+ ``driver_version`` field.
+
+ Driver specific applications can use this information to verify
+ the driver identity. It is also useful to work around known bugs,
+ or to identify drivers in error reports.
+
+ * - char
+ - ``model``\ [32]
+ - Device model name as a NUL-terminated UTF-8 string. The device
+ version is stored in the ``device_version`` field and is not be
+ appended to the model name.
+
+ * - char
+ - ``serial``\ [40]
+ - Serial number as a NUL-terminated ASCII string.
+
+ * - char
+ - ``bus_info``\ [32]
+ - Location of the device in the system as a NUL-terminated ASCII
+ string. This includes the bus type name (PCI, USB, ...) and a
+ bus-specific identifier.
+
+ * - __u32
+ - ``media_version``
+ - Media API version, formatted with the ``KERNEL_VERSION()`` macro.
+
+ * - __u32
+ - ``hw_revision``
+ - Hardware device revision in a driver-specific format.
+
+ * - __u32
+ - ``driver_version``
+ - Media device driver version, formatted with the
+ ``KERNEL_VERSION()`` macro. Together with the ``driver`` field
+ this identifies a particular driver.
+
+ * - __u32
+ - ``reserved``\ [31]
+ - Reserved for future extensions. Drivers and applications must set
+ this array to zero.
+
+The ``serial`` and ``bus_info`` fields can be used to distinguish
+between multiple instances of otherwise identical hardware. The serial
+number takes precedence when provided and can be assumed to be unique.
+If the serial number is an empty string, the ``bus_info`` field can be
+used instead. The ``bus_info`` field is guaranteed to be unique, but can
+vary across reboots or device unplug/replug.
+
+Return Value
+============
+
+On success 0 is returned, on error -1 and the ``errno`` variable is set
+appropriately. The generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.