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1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later2.. c:namespace:: MC3 4.. _media_ioc_setup_link:5 6**************************7ioctl MEDIA_IOC_SETUP_LINK8**************************9 10Name11====12 13MEDIA_IOC_SETUP_LINK - Modify the properties of a link14 15Synopsis16========17 18.. c:macro:: MEDIA_IOC_SETUP_LINK19 20``int ioctl(int fd, MEDIA_IOC_SETUP_LINK, struct media_link_desc *argp)``21 22Arguments23=========24 25``fd``26 File descriptor returned by :c:func:`open()`.27 28``argp``29 Pointer to struct :c:type:`media_link_desc`.30 31Description32===========33 34To change link properties applications fill a struct35:c:type:`media_link_desc` with link identification36information (source and sink pad) and the new requested link flags. They37then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to that38structure.39 40The only configurable property is the ``ENABLED`` link flag to41enable/disable a link. Links marked with the ``IMMUTABLE`` link flag can42not be enabled or disabled.43 44Link configuration has no side effect on other links. If an enabled link45at the sink pad prevents the link from being enabled, the driver returns46with an ``EBUSY`` error code.47 48Only links marked with the ``DYNAMIC`` link flag can be enabled/disabled49while streaming media data. Attempting to enable or disable a streaming50non-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 Value56============57 58On success 0 is returned, on error -1 and the ``errno`` variable is set59appropriately. The generic error codes are described at the60:ref:`Generic Error Codes <gen-errors>` chapter.61 62EINVAL63 The struct :c:type:`media_link_desc` references a64 non-existing link, or the link is immutable and an attempt to modify65 its configuration was made.66