+++ /dev/null
-.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
-
-.. _async:
-
-****************
-Asynchronous I/O
-****************
-
-This method is not defined yet.
in the ``capabilities`` field of struct
:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. At least one of the
-read/write, streaming or asynchronous I/O methods must be supported. VBI
+read/write or streaming I/O methods must be supported. VBI
devices may or may not have a tuner or modulator.
Supplemental Functions
device has an Digital to Analog Converter (DAC), which is a mandatory
element for the SDR transmitter.
-At least one of the read/write, streaming or asynchronous I/O methods
+At least one of the read/write or streaming I/O methods
must be supported.
respectively, in the ``capabilities`` field of struct
:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. At least one of the
-read/write, streaming or asynchronous :ref:`I/O methods <io>` must be
+read/write or streaming :ref:`I/O methods <io>` must be
supported. Sliced VBI devices may have a tuner or modulator.
Supplemental Functions
There are new fields to identify the driver, a new RDS device
function ``V4L2_CAP_RDS_CAPTURE``, the ``V4L2_CAP_AUDIO`` flag
indicates if the device has any audio connectors, another I/O
- capability ``V4L2_CAP_ASYNCIO`` can be flagged. In response to these
+ capability V4L2_CAP_ASYNCIO can be flagged. In response to these
changes the ``type`` field became a bit set and was merged into the
``flags`` field. ``V4L2_FLAG_TUNER`` was renamed to
``V4L2_CAP_TUNER``, ``V4L2_CAP_VIDEO_OVERLAY`` replaced
Other methods must be negotiated. To select the streaming I/O method
with memory mapped or user buffers applications call the
-:ref:`VIDIOC_REQBUFS` ioctl. The asynchronous I/O
-method is not defined yet.
+:ref:`VIDIOC_REQBUFS` ioctl.
Video overlay can be considered another I/O method, although the
application does not directly receive the image data. It is selected by
mmap
userp
dmabuf
- async
buffer
field-order
- 0x01000000
- The device supports the :c:func:`read()` and/or
:c:func:`write()` I/O methods.
- * - ``V4L2_CAP_ASYNCIO``
- - 0x02000000
- - The device supports the :ref:`asynchronous <async>` I/O methods.
* - ``V4L2_CAP_STREAMING``
- 0x04000000
- The device supports the :ref:`streaming <mmap>` I/O method.
#define V4L2_CAP_META_CAPTURE 0x00800000 /* Is a metadata capture device */
#define V4L2_CAP_READWRITE 0x01000000 /* read/write systemcalls */
-#define V4L2_CAP_ASYNCIO 0x02000000 /* async I/O */
#define V4L2_CAP_STREAMING 0x04000000 /* streaming I/O ioctls */
#define V4L2_CAP_META_OUTPUT 0x08000000 /* Is a metadata output device */
#ifndef __KERNEL__
#define V4L2_PIX_FMT_HM12 V4L2_PIX_FMT_NV12_16L16
#define V4L2_PIX_FMT_SUNXI_TILED_NV12 V4L2_PIX_FMT_NV12_32L32
+/*
+ * This capability was never implemented, anyone using this cap should drop it
+ * from their code.
+ */
+#define V4L2_CAP_ASYNCIO 0x02000000
#endif
#endif /* _UAPI__LINUX_VIDEODEV2_H */