1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 3.. _media_ioc_device_info: 4 5*************************** 6ioctl MEDIA_IOC_DEVICE_INFO 7*************************** 8 9Name 10==== 11 12MEDIA_IOC_DEVICE_INFO - Query device information 13 14 15Synopsis 16======== 17 18.. c:function:: int ioctl( int fd, MEDIA_IOC_DEVICE_INFO, struct media_device_info *argp ) 19 :name: MEDIA_IOC_DEVICE_INFO 20 21 22Arguments 23========= 24 25``fd`` 26 File descriptor returned by :ref:`open() <media-func-open>`. 27 28``argp`` 29 Pointer to struct :c:type:`media_device_info`. 30 31 32Description 33=========== 34 35All media devices must support the ``MEDIA_IOC_DEVICE_INFO`` ioctl. To 36query device information, applications call the ioctl with a pointer to 37a struct :c:type:`media_device_info`. The driver 38fills the structure and returns the information to the application. The 39ioctl never fails. 40 41 42.. c:type:: media_device_info 43 44.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 45 46.. flat-table:: struct media_device_info 47 :header-rows: 0 48 :stub-columns: 0 49 :widths: 1 1 2 50 51 52 * - char 53 - ``driver``\ [16] 54 - Name of the driver implementing the media API as a NUL-terminated 55 ASCII string. The driver version is stored in the 56 ``driver_version`` field. 57 58 Driver specific applications can use this information to verify 59 the driver identity. It is also useful to work around known bugs, 60 or to identify drivers in error reports. 61 62 * - char 63 - ``model``\ [32] 64 - Device model name as a NUL-terminated UTF-8 string. The device 65 version is stored in the ``device_version`` field and is not be 66 appended to the model name. 67 68 * - char 69 - ``serial``\ [40] 70 - Serial number as a NUL-terminated ASCII string. 71 72 * - char 73 - ``bus_info``\ [32] 74 - Location of the device in the system as a NUL-terminated ASCII 75 string. This includes the bus type name (PCI, USB, ...) and a 76 bus-specific identifier. 77 78 * - __u32 79 - ``media_version`` 80 - Media API version, formatted with the ``KERNEL_VERSION()`` macro. 81 82 * - __u32 83 - ``hw_revision`` 84 - Hardware device revision in a driver-specific format. 85 86 * - __u32 87 - ``driver_version`` 88 - Media device driver version, formatted with the 89 ``KERNEL_VERSION()`` macro. Together with the ``driver`` field 90 this identifies a particular driver. 91 92 * - __u32 93 - ``reserved``\ [31] 94 - Reserved for future extensions. Drivers and applications must set 95 this array to zero. 96 97 98The ``serial`` and ``bus_info`` fields can be used to distinguish 99between multiple instances of otherwise identical hardware. The serial 100number takes precedence when provided and can be assumed to be unique. 101If the serial number is an empty string, the ``bus_info`` field can be 102used instead. The ``bus_info`` field is guaranteed to be unique, but can 103vary across reboots or device unplug/replug. 104 105 106Return Value 107============ 108 109On success 0 is returned, on error -1 and the ``errno`` variable is set 110appropriately. The generic error codes are described at the 111:ref:`Generic Error Codes <gen-errors>` chapter. 112