1.. -*- coding: utf-8; mode: rst -*- 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 30 31Description 32=========== 33 34All media devices must support the ``MEDIA_IOC_DEVICE_INFO`` ioctl. To 35query device information, applications call the ioctl with a pointer to 36a struct :c:type:`media_device_info`. The driver 37fills the structure and returns the information to the application. The 38ioctl never fails. 39 40 41.. c:type:: media_device_info 42 43.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 44 45.. flat-table:: struct media_device_info 46 :header-rows: 0 47 :stub-columns: 0 48 :widths: 1 1 2 49 50 51 * - char 52 - ``driver``\ [16] 53 - Name of the driver implementing the media API as a NUL-terminated 54 ASCII string. The driver version is stored in the 55 ``driver_version`` field. 56 57 Driver specific applications can use this information to verify 58 the driver identity. It is also useful to work around known bugs, 59 or to identify drivers in error reports. 60 61 * - char 62 - ``model``\ [32] 63 - Device model name as a NUL-terminated UTF-8 string. The device 64 version is stored in the ``device_version`` field and is not be 65 appended to the model name. 66 67 * - char 68 - ``serial``\ [40] 69 - Serial number as a NUL-terminated ASCII string. 70 71 * - char 72 - ``bus_info``\ [32] 73 - Location of the device in the system as a NUL-terminated ASCII 74 string. This includes the bus type name (PCI, USB, ...) and a 75 bus-specific identifier. 76 77 * - __u32 78 - ``media_version`` 79 - Media API version, formatted with the ``KERNEL_VERSION()`` macro. 80 81 * - __u32 82 - ``hw_revision`` 83 - Hardware device revision in a driver-specific format. 84 85 * - __u32 86 - ``driver_version`` 87 - Media device driver version, formatted with the 88 ``KERNEL_VERSION()`` macro. Together with the ``driver`` field 89 this identifies a particular driver. 90 91 * - __u32 92 - ``reserved``\ [31] 93 - Reserved for future extensions. Drivers and applications must set 94 this array to zero. 95 96 97The ``serial`` and ``bus_info`` fields can be used to distinguish 98between multiple instances of otherwise identical hardware. The serial 99number takes precedence when provided and can be assumed to be unique. 100If the serial number is an empty string, the ``bus_info`` field can be 101used instead. The ``bus_info`` field is guaranteed to be unique, but can 102vary across reboots or device unplug/replug. 103 104 105Return Value 106============ 107 108On success 0 is returned, on error -1 and the ``errno`` variable is set 109appropriately. The generic error codes are described at the 110:ref:`Generic Error Codes <gen-errors>` chapter. 111