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| -rw-r--r-- | Documentation/userspace-api/media/mediactl/media-request-ioc-reinit.rst | 51 |
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diff --git a/Documentation/userspace-api/media/mediactl/media-request-ioc-reinit.rst b/Documentation/userspace-api/media/mediactl/media-request-ioc-reinit.rst new file mode 100644 index 0000000000..57567b87b9 --- /dev/null +++ b/Documentation/userspace-api/media/mediactl/media-request-ioc-reinit.rst @@ -0,0 +1,51 @@ +.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later +.. c:namespace:: MC + +.. _media_request_ioc_reinit: + +****************************** +ioctl MEDIA_REQUEST_IOC_REINIT +****************************** + +Name +==== + +MEDIA_REQUEST_IOC_REINIT - Re-initialize a request + +Synopsis +======== + +.. c:macro:: MEDIA_REQUEST_IOC_REINIT + +``int ioctl(int request_fd, MEDIA_REQUEST_IOC_REINIT)`` + +Arguments +========= + +``request_fd`` + File descriptor returned by :ref:`MEDIA_IOC_REQUEST_ALLOC`. + +Description +=========== + +If the media device supports :ref:`requests <media-request-api>`, then +this request ioctl can be used to re-initialize a previously allocated +request. + +Re-initializing a request will clear any existing data from the request. +This avoids having to :c:func:`close()` a completed +request and allocate a new request. Instead the completed request can just +be re-initialized and it is ready to be used again. + +A request can only be re-initialized if it either has not been queued +yet, or if it was queued and completed. Otherwise it will set ``errno`` +to ``EBUSY``. No other error codes can be returned. + +Return Value +============ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. + +EBUSY + The request is queued but not yet completed. |