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.

       -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.

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)