1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2.. c:namespace:: MC 3 4.. _media_ioc_setup_link: 5 6************************** 7ioctl MEDIA_IOC_SETUP_LINK 8************************** 9 10Name 11==== 12 13MEDIA_IOC_SETUP_LINK - Modify the properties of a link 14 15Synopsis 16======== 17 18.. c:macro:: MEDIA_IOC_SETUP_LINK 19 20``int ioctl(int fd, MEDIA_IOC_SETUP_LINK, struct media_link_desc *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_link_desc`. 30 31Description 32=========== 33 34To change link properties applications fill a struct 35:c:type:`media_link_desc` with link identification 36information (source and sink pad) and the new requested link flags. They 37then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to that 38structure. 39 40The only configurable property is the ``ENABLED`` link flag to 41enable/disable a link. Links marked with the ``IMMUTABLE`` link flag can 42not be enabled or disabled. 43 44Link configuration has no side effect on other links. If an enabled link 45at the sink pad prevents the link from being enabled, the driver returns 46with an ``EBUSY`` error code. 47 48Only links marked with the ``DYNAMIC`` link flag can be enabled/disabled 49while streaming media data. Attempting to enable or disable a streaming 50non-dynamic link will return an ``EBUSY`` error code. 51 52If the specified link can't be found the driver returns with an ``EINVAL`` 53error code. 54 55Return Value 56============ 57 58On success 0 is returned, on error -1 and the ``errno`` variable is set 59appropriately. The generic error codes are described at the 60:ref:`Generic Error Codes <gen-errors>` chapter. 61 62EINVAL 63 The struct :c:type:`media_link_desc` references a 64 non-existing link, or the link is immutable and an attempt to modify 65 its configuration was made. 66