LG G3 - PC Mode Reactivates After Cold Boot on Nvidia and Intel, but not AMD GPU

[atcronin]

I remember when I first bought the TV in Nov '23, it would switch into PC mode (setting the HDMI input to PC) automatically when first connecting my RTX 4090 PC. This behaviour was fine as the TV was indeed being used for PC Gaming.

On my RTX 3050 HTPC I could disable PC mode by changing the input back to HDMI1. This would restore all picture settings options. This change would persist until the HDMI cable was physically disconnected/reconnected. Again, this behaviour was fine for my HTPC where I preferred having access to all the picture settings options vs 444 passthrough.

 

Now PC mode is reactivated after every Cold Boot (Shutdown > Power On) but not from Warm Boot (Restart).

It is a 'silent' PC mode as the input label does not change back to PC, however the same picture settings are greyed out like in PC mode. Switching the Input label from HDMI1 to another non-PC type disables PC mode again and restores the full picture settings.

 

I was using the RTX 3050 in my HTPC for a few months after I purchased the TV and did not experience this issue. After a few months I switched to the RX 7600 and continued to not experience this issue. I recently tried going back to the Intel iGPU on the HTPC and discovered this issue. I thought it might be an intel bug, so I reinstalled the RTX 3050 and found the issue again. I've gone back to the RX 7600 as it does not suffer this issue.

 

I have Game Optimizer options disabled (VRR, Freesync, ALLM), 444 Passthrough Disabled, QMS Disabled.

Intel and Nvidia GPU options tried:

Change output from RGB to YCBCR = no effect

Disable "Text Content Processing" on intel = no effect

Change "Content type reported" on Nvidia = no effect (Movie does activate film maker mode)

 

Testing performed on Win11 24H2, however also experienced the issue when testing LibreElec(Linux Distro for Kodi) on the intel iGPUs (didn't test Nvidia in LibreElec as unsupported).

 

Affected GPUs: UHD Graphics 730 on Intel i5-11400 and i3-12100, Nvidia RTX 3050

Unaffected GPUs: AMD RX 7600, Nvidia GT 1030

 

I've noticed that on the RX 7600 and GT 1030 the SPD Info Frame are blank/Unknown.

While on the UHD 730 - Product Description: PC, Vendor Name: Intel, Source Info: PC

and the RTX 3050 - Product Description: GeForce RTX 3050, Vendor Name: NVIDIA, Source Info: PC