1 .. SPDX-License-Identifier: GPL-2.0
2
3 Digital TV Common functions
4 ---------------------------
5
6 DVB devices
7 ~~~~~~~~~~~
8
9 Those functions are responsible for handling t
10
11 .. kernel-doc:: include/media/dvbdev.h
12
13 Digital TV Ring buffer
14 ~~~~~~~~~~~~~~~~~~~~~~
15
16 Those routines implement ring buffers used to
17 copy it from/to userspace.
18
19 .. note::
20
21 1) For performance reasons read and write ro
22 and/or number of bytes free/available. Th
23 routines are called. For example:
24
25 .. code-block:: c
26
27 /* write @buflen: bytes */
28 free = dvb_ringbuffer_free(rbuf);
29 if (free >= buflen)
30 count = dvb_ringbuffer_write(r
31 else
32 /* do something */
33
34 /* read min. 1000, max. @bufsize: byte
35 avail = dvb_ringbuffer_avail(rbuf);
36 if (avail >= 1000)
37 count = dvb_ringbuffer_read(rb
38 else
39 /* do something */
40
41 2) If there is exactly one reader and one wr
42 to lock read or write operations.
43 Two or more readers must be locked agains
44 Flushing the buffer counts as a read oper
45 Resetting the buffer counts as a read and
46 Two or more writers must be locked agains
47
48 .. kernel-doc:: include/media/dvb_ringbuffer.h
49
50 Digital TV VB2 handler
51 ~~~~~~~~~~~~~~~~~~~~~~
52
53 .. kernel-doc:: include/media/dvb_vb2.h
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