1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2.. c:namespace:: MC
3
4.. _media_ioc_device_info:
5
6***************************
7ioctl MEDIA_IOC_DEVICE_INFO
8***************************
9
10Name
11====
12
13MEDIA_IOC_DEVICE_INFO - Query device information
14
15Synopsis
16========
17
18.. c:macro:: MEDIA_IOC_DEVICE_INFO
19
20``int ioctl(int fd, MEDIA_IOC_DEVICE_INFO, struct media_device_info *argp)``
21
22Arguments
23=========
24
25``fd``
26    File descriptor returned by :c:func:`open()`.
27
28``argp``
29    Pointer to struct :c:type:`media_device_info`.
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.. c:type:: media_device_info
41
42.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
43
44.. flat-table:: struct media_device_info
45    :header-rows:  0
46    :stub-columns: 0
47    :widths:       1 1 2
48
49    *  -  char
50       -  ``driver``\ [16]
51       -  Name of the driver implementing the media API as a NUL-terminated
52	  ASCII string. The driver version is stored in the
53	  ``driver_version`` field.
54
55	  Driver specific applications can use this information to verify
56	  the driver identity. It is also useful to work around known bugs,
57	  or to identify drivers in error reports.
58
59    *  -  char
60       -  ``model``\ [32]
61       -  Device model name as a NUL-terminated UTF-8 string. The device
62	  version is stored in the ``device_version`` field and is not be
63	  appended to the model name.
64
65    *  -  char
66       -  ``serial``\ [40]
67       -  Serial number as a NUL-terminated ASCII string.
68
69    *  -  char
70       -  ``bus_info``\ [32]
71       -  Location of the device in the system as a NUL-terminated ASCII
72	  string. This includes the bus type name (PCI, USB, ...) and a
73	  bus-specific identifier.
74
75    *  -  __u32
76       -  ``media_version``
77       -  Media API version, formatted with the ``KERNEL_VERSION()`` macro.
78
79    *  -  __u32
80       -  ``hw_revision``
81       -  Hardware device revision in a driver-specific format.
82
83    *  -  __u32
84       -  ``driver_version``
85       -  Media device driver version, formatted with the
86	  ``KERNEL_VERSION()`` macro. Together with the ``driver`` field
87	  this identifies a particular driver.
88
89    *  -  __u32
90       -  ``reserved``\ [31]
91       -  Reserved for future extensions. Drivers and applications must set
92	  this array to zero.
93
94The ``serial`` and ``bus_info`` fields can be used to distinguish
95between multiple instances of otherwise identical hardware. The serial
96number takes precedence when provided and can be assumed to be unique.
97If the serial number is an empty string, the ``bus_info`` field can be
98used instead. The ``bus_info`` field is guaranteed to be unique, but can
99vary across reboots or device unplug/replug.
100
101Return Value
102============
103
104On success 0 is returned, on error -1 and the ``errno`` variable is set
105appropriately. The generic error codes are described at the
106:ref:`Generic Error Codes <gen-errors>` chapter.
107