| .. -*- coding: utf-8; mode: rst -*- |
| |
| .. _media_ioc_device_info: |
| |
| *************************** |
| ioctl MEDIA_IOC_DEVICE_INFO |
| *************************** |
| |
| Name |
| ==== |
| |
| MEDIA_IOC_DEVICE_INFO - Query device information |
| |
| |
| Synopsis |
| ======== |
| |
| .. c:function:: int ioctl( int fd, int request, struct media_device_info *argp ) |
| |
| |
| Arguments |
| ========= |
| |
| ``fd`` |
| File descriptor returned by :ref:`open() <media-func-open>`. |
| |
| ``request`` |
| MEDIA_IOC_DEVICE_INFO |
| |
| ``argp`` |
| |
| |
| 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 :ref:`media_device_info <media-device-info>`. The driver |
| fills the structure and returns the information to the application. The |
| ioctl never fails. |
| |
| |
| .. _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 |
| |
| |
| - .. row 1 |
| |
| - 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. |
| |
| - .. row 2 |
| |
| - 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. |
| |
| - .. row 3 |
| |
| - char |
| |
| - ``serial``\ [40] |
| |
| - Serial number as a NUL-terminated ASCII string. |
| |
| - .. row 4 |
| |
| - 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. |
| |
| - .. row 5 |
| |
| - __u32 |
| |
| - ``media_version`` |
| |
| - Media API version, formatted with the ``KERNEL_VERSION()`` macro. |
| |
| - .. row 6 |
| |
| - __u32 |
| |
| - ``hw_revision`` |
| |
| - Hardware device revision in a driver-specific format. |
| |
| - .. row 7 |
| |
| - __u32 |
| |
| - ``driver_version`` |
| |
| - Media device driver version, formatted with the |
| ``KERNEL_VERSION()`` macro. Together with the ``driver`` field |
| this identifies a particular driver. |
| |
| - .. row 8 |
| |
| - __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. |