1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 .. c:namespace:: MC 3 4 .. _media_ioc_setup_link: 5 6 ************************** 7 ioctl MEDIA_IOC_SETUP_LINK 8 ************************** 9 10 Name 11 ==== 12 13 MEDIA_IOC_SETUP_LINK - Modify the properties of a link 14 15 Synopsis 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 22 Arguments 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 31 Description 32 =========== 33 34 To change link properties applications fill a struct 35 :c:type:`media_link_desc` with link identification 36 information (source and sink pad) and the new requested link flags. They 37 then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to that 38 structure. 39 40 The only configurable property is the ``ENABLED`` link flag to 41 enable/disable a link. Links marked with the ``IMMUTABLE`` link flag can 42 not be enabled or disabled. 43 44 Link configuration has no side effect on other links. If an enabled link 45 at the sink pad prevents the link from being enabled, the driver returns 46 with an ``EBUSY`` error code. 47 48 Only links marked with the ``DYNAMIC`` link flag can be enabled/disabled 49 while streaming media data. Attempting to enable or disable a streaming 50 non-dynamic link will return an ``EBUSY`` error code. 51 52 If the specified link can't be found the driver returns with an ``EINVAL`` 53 error code. 54 55 Return Value 56 ============ 57 58 On success 0 is returned, on error -1 and the ``errno`` variable is set 59 appropriately. The generic error codes are described at the 60 :ref:`Generic Error Codes <gen-errors>` chapter. 61 62 EINVAL 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.
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