[REQUEST] HDMI-CEC support for Linux on Framework Desktop?

[Hedda]

I would like request that native HDMI-CEC support gets added to Framework Desktop and working out-of-the-box with open-source code working under Linux operating systems.

• https://en.wikipedia.org/wiki/Consumer_Electronics_Control

HDMI-CEC is a serial-protocol that can be users over onve of the HDMI port pins to control Televisions, audio-recievers, and HDMI-switches. with some having support mainline Linux kernel.

• https://docs.kernel.org/admin-guide/media/cec.html

  • https://wiki.archlinux.org/title/HDMI-CEC

The use case is that this is normally available as a feature for different types Linux-based HTPC (Home Theater PC) computers, and perhaps now just as interesting the upcoming new official “Steam Machine” computer in a game-console form-factor running SteamOS operating-system from Valve (as SteamOS is a Linux OS that has built in CEC support).

• https://en.wikipedia.org/wiki/Home_theater_PC

This feature is therefore epecially wanted on any mini-PCs that can be used as HTPC (Home Theater PC) with example LibreELEC or game-consoles with SteamOS or as a HTPC (Home Theater PC) with example Kodi media center (under the LibreELEC operating system).

• https://en.wikipedia.org/wiki/LibreELEC

  • https://en.wikipedia.org/wiki/Kodi_(software)

Again, many users will soon probably be interested in installing the SteamOS recovery image on the Framework Desktop too, and that will at least have built-in support for HDMI-CEC on Valve's official upcoming Steam Machine hardware, which is partially somewhat similar to the AMD-based hardware platform used in the Framework Desktop (but better), with the exception of having HDMI-CEC working out-of-the-box which is the key part that will make it more user-friendly when connected to a television in the living-room:

• https://help.steampowered.com/en/faqs/view/1b71-edf2-eb6d-2bb3

  • https://store.steampowered.com/sale/steammachine

If the onboard motherboard of the current Framework Desktop do not support this in hardware (which the specification does say that it does) then you might instead technically need an additional MCU (microcontroller unit) module like an ESP32 or Atmel that has a GPIO pins for seial interface connected to the HDMI-CEC pins (for CEC out and CEC in ports) to achieve this. That is, if it works like any other modern computer you probably want to use an ESP32 MCU instead of an older Atmel because it will encurange easier development from the end-user community. Then on that microcontroller you use some kind of Arduino library which implements the HDMI CEC wire protocol which allows communication with HDMI CEC capable devices.

See examples these open-source projects on GitHub with libraries that could be used to implement a CEC firmeware for an MCU.

• https://github.com/gkoh/pico-cec
• https://github.com/Pulse-Eight/libcec
• https://github.com/floe/CEC
• https://github.com/Palakis/esphome-native-hdmi-cec
• https://github.com/SzymonSlupik/CEC-Tiny

[kiram9]

CEC firmware support did not land for this program. However the hardware is present. This will require developing a bitbang CEC implementation in the EC firmware. As the EC does not have any dedicated CEC peripherals to drive the CEC bus.

CEC OUT (from EC) GPIO96/F_DIO1
CEC In (To EC) GPIO40/TA1

[Hedda]

CEC firmware support did not land for this program. However the hardware is present. This will require developing a bitbang CEC implementation in the EC firmware. As the EC does not have any dedicated CEC peripherals to drive the CEC bus.

@kiram9 Do you think that there is any chance that Framework Computer would add that to their roadmap for the Framework Desktop motherboard series?

Again, hoping here that an initial goal could be for the for the Framework Desktop motherboard to match the HDMI-CEC support of the upcoming Steam Machine hardware from Valve as well as have CEC software compability with that Valve have added or will add to their SteamOS image (Steam OS recovery image) for the Steam Deck, which more importantly is also what they will be use on the Steam Machine hardware.

• https://help.steampowered.com/en/faqs/view/65B4-2AA3-5F37-4227

• https://help.steampowered.com/en/faqs/view/1B71-EDF2-EB6D-2BB3

• https://store.steampowered.com/steamos/download/?ver=steamdeck&snr

Same goes for those user LibreELEC OS for Kodi as a media player to use the Framework Desktop as a HTPC in their living-rooms.

• https://libreelec.tv

  • https://kodi.wiki/view/CEC

The point here is that those that want to run SteamOS on the Framework Desktop motherboard should not have to buy an external HDMI-CEC USB-adapter with HDMI-passthrough to get this functionality when running SteamOS or LibreELEC (Kodi/XBMC), instead it should be enough to just have the the barebone hardware with built-in native HDMI-CEC support.

PS: For reference and good real world use case you might still be interested to check out the USB-CEC Adapter from Pulse-Eight:

• https://www.pulse-eight.com/p/104/usb-hdmi-cec-adapter

  • https://github.com/Pulse-Eight/libcec

    Pulse-Eight USB CEC Adapter Technical Demonstration video:

  • https://www.youtube.com/watch?v=1eDJbT35X5k

PPS: Raspberry Pi also has embedded CEC support and is supported by Pulse-Eight's libCEC and is therefore fully supported by Kodi:

• https://libcec.pulse-eight.com/