| .. -*- coding: utf-8; mode: rst -*- |
| |
| .. _media_ioc_setup_link: |
| |
| ************************** |
| ioctl MEDIA_IOC_SETUP_LINK |
| ************************** |
| |
| Name |
| ==== |
| |
| MEDIA_IOC_SETUP_LINK - Modify the properties of a link |
| |
| |
| Synopsis |
| ======== |
| |
| .. c:function:: int ioctl( int fd, MEDIA_IOC_SETUP_LINK, struct media_link_desc *argp ) |
| :name: MEDIA_IOC_SETUP_LINK |
| |
| |
| Arguments |
| ========= |
| |
| ``fd`` |
| File descriptor returned by :ref:`open() <media-func-open>`. |
| |
| ``argp`` |
| |
| |
| Description |
| =========== |
| |
| To change link properties applications fill a struct |
| :c:type:`media_link_desc` with link identification |
| information (source and sink pad) and the new requested link flags. They |
| then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to that |
| structure. |
| |
| The only configurable property is the ``ENABLED`` link flag to |
| enable/disable a link. Links marked with the ``IMMUTABLE`` link flag can |
| not be enabled or disabled. |
| |
| Link configuration has no side effect on other links. If an enabled link |
| at the sink pad prevents the link from being enabled, the driver returns |
| with an ``EBUSY`` error code. |
| |
| Only links marked with the ``DYNAMIC`` link flag can be enabled/disabled |
| while streaming media data. Attempting to enable or disable a streaming |
| non-dynamic link will return an ``EBUSY`` error code. |
| |
| If the specified link can't be found the driver returns with an ``EINVAL`` |
| error code. |
| |
| |
| 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 |
| :ref:`Generic Error Codes <gen-errors>` chapter. |
| |
| EINVAL |
| The struct :c:type:`media_link_desc` references a |
| non-existing link, or the link is immutable and an attempt to modify |
| its configuration was made. |
