Ubuntu Manpage: cec-follower - An application to emulate CEC followers

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 functionalities 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 arrive and taking the
appropriate action for each message (incoming messages 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 violations 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 device 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 device 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 addresses or opcodes.

       --ignore-standby <n>
              Ignore every <n>th received Standby message.

       --ignore-view-on <n>
              Ignore every <n>th received Image/Text View On message.

EXIT STATUS

       On success, it returns 0. Otherwise, it will return the error code.

BUGS