CEC-FOLLOWER(1) User Commands CEC-FOLLOWER(1)
NAME
cec-follower - An application to emulate CEC followers
SYNOPSIS
cec-follower [-h] [-d <dev>] [other options]
DESCRIPTION
The cec-follower tool is used to emulate CEC followers. Based on the
configured logical address(es) of the CEC device it will emulate the
CEC behavior accordingly.
Configuring the CEC device is done using cec-ctl. Certain CEC function-
alities are only emulated if the corresponding Device Features flag is
set (these are set when configuring with cec-ctl). These are:
- Audio Return Channel (RX and TX)
- Audio Rate Control
- Deck Control
- Record TV screen
cec-follower is basically a message loop, waiting for messages to ar-
rive and taking the appropriate action for each message (incoming mes-
sages can be shown with the --show-msgs option). The follower maintains
an internal state with appropriate parameters such as volume, current
active source, power state and so on (state changes can be shown with
the --show-state option).
It also aims to be a reference implementation on how a follower should
behave.
cec-follower will keep track of incoming messages and look for viola-
tions of the CEC specification with regards to timings. For example, it
will warn if it receives the same message again within 200ms after it
replied <Feature Abort> ["Unrecognized Opcode"] to that message, and it
will check that press and hold behavior is done properly.
cec-follower will periodically send out polling messages to discover
when a remote device is removed or a new one has appeared. When a de-
vice is removed, the recorded information about it is cleared. Each
logical address is polled about once every 15 seconds. In between
polls, removing a remote device or replacing it with a new one is not
detected.
When running compliance tests with cec-compliance, cec-follower should
be run on the same device to act on incoming messages that are not
replies to messages sent by the compliance tool. Before each test-run
cec-follower should be restarted if it is running, to initialize the
emulated device with a clean and known initial state.
OPTIONS
-d, --device <dev>
Use device <dev> as the CEC device. If <dev> is a number, then
/dev/cec<dev> is used.
-D, --driver <drv>
Use a cec device that has driver name <drv>, as returned by the
CEC_ADAP_G_CAPS ioctl. This option can be combined with -a to
uniquely identify a CEC device without having to rely on the de-
vice node number.
-a, --adapter <adap-name>
Use a cec device that has adapter name <adap-name>, as returned
by the CEC_ADAP_G_CAPS ioctl. This option can be combined with
-D to uniquely identify a CEC device without having to rely on
the device node number.
-v, --verbose
Turn on verbose reporting.
--version
Show version information.
-w, --wall-clock
Show timestamps as wall-clock time. This also turns on verbose
reporting.
-T, --trace
Trace all called ioctls. Useful for debugging.
-h, --help
Prints the help message.
-n, --no-warnings
Turn off warning messages.
-m, --show-msgs
Show received messages.
-s, --show-state
Show state changes from the emulated device.
--service-by-dig-id
Report digital services by digital ID instead of by channel.
--standby
Start the follower in the Standby status.
--toggle-power-status <secs>
Toggle the power status every <secs> seconds. Only supported if
the follower is emulating a TV.
-i, --ignore <la>,<opcode>
Ignore messages from logical address <la> and opcode <opcode>.
'all' can be used for <la> or <opcode> to match all logical ad-
dresses or opcodes.
EXIT STATUS
On success, it returns 0. Otherwise, it will return the error code.
BUGS
This manual page is a work in progress.
Bug reports or questions about this utility should be sent to the
linux-media@vger.kernel.org mailinglist.
SEE ALSO
cec-compliance(1), cec-ctl(1)
v4l-utils 1.22.1 August 2016 CEC-FOLLOWER(1)
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