IMX8M Plus - no cec when LCDIF3 is disabled in devicetree

[robot1]

Dear NXP

On my CompuLab IMX8M board is have cec fully functional (/dev/cec0) when lcdif3 is enabled in devicetree.

This on linux 5.15.71.

However as soon as I disable lcdif3 /dev/cec0 is still available but no information/negotiation is updated in:

root@mydevice:~# cat /sys/kernel/debug/cec/cec0/status
configured: 0
configuring: 0
phys_addr: f.f.f.f
number of LAs: 0
LA mask: 0x0000
pending transmits: 0

Everything hdmi related I can think off is still enabled ("okay") in devicetree: hdmi, pavi, phy etc...

Can I still use ARC / eARC /DDC /CEC when lcdif3 is disabled?

The main reason I need to disable lcdif3 is that I don not need HDMI video and I want to save power in standby, but still be able to wake on cec command.

Thanks in advance.

Flemming

[Bio_TICFSL]

Hello,

Yes you can use ARC when lcdif3 is disable just check the dtb is according to what you desire.

I would recommend moving to a newer version of the BSP if possible.

Regards

[robot1]

Thanks "Bio"

It is not a good time in the project to update BSP, but I may cherrypick specific relevant files.

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Good to know that CEC and ARC should work with lcdif3 disabled.

Then we just need to find out why it is not working! 

Any idea? Where to look/debug? Clocktree? HPD? Other? 

Kind regard Flemming