On Mon, Jul 31, 2017 at 11:13 PM, Luke Kenneth Casson Leighton lkcl@lkcl.net wrote:
CEC etc i believe is supported i can't remember the details, it's covered by the processor and is somewhere in the datasheet. certainly i know there's an hdmi audio kernel module for sound playback in the sunxi-3.4 kernel.
Sorry, I explain things well enough. Sound playback normally refers to sound output from the kernel to D/A, amplifier, and speakers. Same direction as video playback: from computer to monitor.
CEC: Consumer Electronics Control Allows devices to pass control information around. Say you have a remote control for your television that has "Play" and "Pause" buttons on it, for instance. Through CEC the commands could be sent from your television to the EOMA68-A20 card via the HDMI cable and software there could respond appropriately to the events.
ARC: Audio Return Channel The Audio Return Channel supports sending digital multi-channel sound upstream (for input to the computer). This would allow recording, mixing, special effects, etc.
so *i'm* not quotes considering it quotes - if it's there and there's a linux kernel module it's there, people can compile it and use it.
From the sound of things, CEC was there from the beginning and ARC is
new in v1.4 but doesn't require circuit changes on the HDMI transmitter PCB to accommodate. ARC does require support in the HDMI block/subsystem of the SoC.
On the other hand, if we plan to support HEC (HDMI Ethernet Channel) it requires us to route one more pair of signals as a differential pair.