I have an AV Receiver that I want to turn on from standby using cec-client on raspberry pi. The physicall setup is as follows:
RPI --HDMI--> AV Receiver
TV <--ARC_HDMI--> AV Receiver
Scanning my HDMI devices with echo "scan" | cec-client -s -d 1 I get following output:
opening a connection to the CEC adapter...
requesting CEC bus information ...
CEC bus information
===================
device #0: TV
address: 0.0.0.0
active source: no
vendor: Samsung
osd string: TV
CEC version: unknown
power status: standby
language: ger
device #1: Recorder 1
address: 1.0.0.0
active source: no
vendor: Pulse Eight
osd string: CECTester
CEC version: 1.4
power status: on
language: eng
device #5: Audio
address: 3.0.0.0
active source: no
vendor: Harman/Kardon
osd string: H/K AVR
CEC version: 1.4
power status: standby
language: ???
As you can see, my AV Receiver has the device number #5 and physical address 3.0.0.0
I tried following already, using cec-o-matic as reference:
echo "on 3.0.0.0" | cec-client -s -d 0
echo "on 5" | cec-client -s -d 0
echo "tx 15:04" | cec-client -s -d 0
But neither command turns on the AV Receiver. The same commands addressing the TV work without an issue.
After a lot of trial and error, I found out that rebooting my Raspberry Pi actually turns on the receiver! Nice, at least something. Investigating further I found out that in /boot/config.txt one can add/set the hdmi_ignore_cec_init=1 parameter to indicate whether the Raspberry Pi should send an active source message while rebooting. Depending on whether this is set to 0 or 1 my AV receiver turns on when I boot/reboot my RPI.
Now, I obviously don't want to reboot my RPI whenever I want to turn on my AV Receiver. So my question is what is the specific CEC-message the Raspberry sends on boot, so I can replicate it with the cec-client with something along the lines of echo "tx <specific-cec-message>" | cec-client -s -d 1
I already tried monitoring cec traffic on boot with cec-client -f cec.log, but monitoring starts too late and misses the send signal from RPI on boot.
The easiest way to find this out would probably to have a second Raspberry Pi monitoring the bus while the other one boots, but I only have 1 RPI, so I can not test it myself.
Does anyone have an idea, or at least a source for me? Big Thanks for taking the time!
In case it matters here also the specific device models.
TV: Samsung ue55f8090
AVR: Harman Kardon AVR 156
RPI: Raspberry Pi 4 Model B Rev 1.4
RPI_OS: Raspbian GNU/Linux 10 (buster) armv
RPI_KERNEL: Kernel: 5.10.103-v7l+
