5.9. ioctl MEDIA_IOC_REQUEST_ALLOC¶
MEDIA_IOC_REQUEST_ALLOC - Allocate a request
File descriptor returned by
Pointer to an integer.
If the media device supports requests, then
this ioctl can be used to allocate a request. If it is not supported, then
errno is set to
ENOTTY. A request is accessed through a file descriptor
that is returned in
Finally, the file descriptor can be polled to wait for the request to complete.
The request will remain allocated until all the file descriptors associated
with it are closed by
close() and the driver no
longer uses the request internally. See also
here for more information.