HDMI Ethernet Channel - Would it work?

[Spider.007]

I am not too familiar with Ethernet over HDMI, since I don't own any devices that support it, but I was wondering; would it be possible (in the future) to use this feature on the RPi? Is there anything physically allowing or preventing usage of this?

More information on HDMI Ethernet Channel

[mahjongg]

The SoC doesn't support the ethernet channel, (I have heard) so no it won't ever be supported.

[JeremyF]

The HDMI port can not receive Ethernet signals. Since it is related topic, the Ethernet cannot receive power. (PoE)

[ds18s20]

I can confirm: NO Ethernet via HDMI. I plugged my Raspi into my Bravia TV and the TV does not report the Ethernet HDMI interface as active.

When I plug my Blu-ray player (which supports Ethernet over HDMI) into the same HDMI port on the TV then the HDMI Ethernet interface shows up as active using the Bravia diagnostics screen under system menu.

Oh well...

[tediffer3rd]

Then how can I control my 512 meg RasPi with my TV remote?

[toxibunny]

CEC. http://en.wikipedia.org/wiki/HDMI#CEC

[adammw]

Do you know if the SoC also does not support HDMI ARC? Both are part of the HDMI 1.4 spec. What exactly in the SoC is preventing this sort of data from being accessible to the cpu, why does it allow CEC access but not the other channels? Or is it related to the closed source parts of the firmware?

[drgeoff]

Do you know if the SoC also does not support HDMI ARC? Both are part of the HDMI 1.4 spec. What exactly in the SoC is preventing this sort of data from being accessible to the cpu, why does it allow CEC access but not the other channels? Or is it related to the closed source parts of the firmware?

From Wikipedia's page about HDMI:

"HDMI 1.4 introduces two features called ARC (Audio Return Channel) and HEC (HDMI Ethernet Channel).[58][59][93] These features use two pins from the connector: a previously unused pin and the hot plug detect pin."

If the previously unused pin does not go anywhere in the Broadcom SoC (I don't know) then whatever feature needs it now will never work. Similarly there may be an internal hardware limitation which prevents use of the hot plug detect pin for other than what was in the SoC's original requirements specification.

[rpdom]

It would help if that article said which pin was "previously unused", as the Pi schematics are freely available to check.

[drgeoff]

It would help if that article said which pin was "previously unused", as the Pi schematics are freely available to check.

It does say. Look underneath the first picture on the right hand side. There is a list of the pins and it specifically mentions Reserved/HEC for pin 14.

Even if the HDMI socket's pin is connected to the SoC, that doesn't mean it goes anywhere useful inside the SoC!

[jamesh]

No, the SoC does not support ethernet over HDMI.

[cortb]

is this still the case for the pi 2/3?

[6by9]

is this still the case for the pi 2/3?

Yes.

[hemant]

Still the same for pi 4?

[rpdom]

Yes.

[ludoplex]

Is this still the case for Pi Zero and Pi Zero W?

What about RPI B+ 3?

[6by9]

The pi zero is the same soc as on the original Pis, so guidance there would still be the same.
No, it's not supported on any of the newer variants either.

[cleverca22]

one theory ive looked at a bit, but i'm not sure how feasible it would be

could you make an adapter that just has hdmi+ethernet on one end, and hdmi on the other?, and just break the signals out before they dead-end in the pi

then just plug the cable into both the hdmi and ethernet ports, and your done!

the wonky single-differential pair for ethernet instead of the normal rx and tx pairs, might make it harder to implement...