Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 66 insertions, 0 deletions

diff --git a/Documentation/media/uapi/mediactl/media-ioc-setup-link.rst b/Documentation/media/uapi/mediactl/media-ioc-setup-link.rst
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+.. -*- 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.