107 lines
3.0 KiB
ReStructuredText
107 lines
3.0 KiB
ReStructuredText
.. 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{8.5cm}|
|
|
|
|
.. 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.
|