5.4. ioctl MEDIA_IOC_DEVICE_INFO

5.4.1. Name

MEDIA_IOC_DEVICE_INFO - Query device information

5.4.2. Synopsis

MEDIA_IOC_DEVICE_INFO

int ioctl(int fd, MEDIA_IOC_DEVICE_INFO, struct media_device_info *argp)

5.4.3. Arguments

fd

File descriptor returned by open().

argp

Pointer to struct media_device_info.

5.4.4. 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 media_device_info. The driver fills the structure and returns the information to the application. The ioctl never fails.

media_device_info

struct media_device_info

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.

5.4.5. 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 Generic Error Codes chapter.