[ktide1]

Much thanks to Warner306 for this excellent guide.  I'm setup with Kodi 18, MPC-BE, and madvr and overall everything is working well including HDR passthrough.

However, I keep having a small problem I'm hoping someone here can help with.  I'm using a GTX 1060 (6GB version) with the 385.28 Nvidia driver on Windows 10 1903.  No matter what I do, I cannot get RGB Full to stick in the Nvidia control panel.  For reference, the GTX 1060 is connected via HDMI to a Denon x3400h AVR, then to a Samsung KS8000 TV.  UHD color, color space settings, etc. are all set up correctly on all devices, with the intent of using RGB Full throughout the chain as suggested.  The HTPC is "always on" and I typically leave Kodi running all the time.

I've been through all the refresh rates, setting them up as suggested - i.e. 12-bit color for 30 Hz and below, 8-bit for everything else with RGB at full dynamic range.  When I set it, it will stay like that initially.  I can launch Kodi and it sticks, play a movie using MPC-BE as external player, no problems - so far so good.  It will even survive a reboot, no problem.  madvr reports the correct bit depth and all looks good.

However, if I switch off the AVR and TV (leaving the PC on and Kodi running) and come back later, say the next day, and turn everything back on again, it's immediately obvious the color settings have been changed to limited without anyone touching anything.  I can go back into the Nvidia control panel and re-select "Full" on dynamic range, click "Apply" and everything returns to normal.  Also another interesting anomaly is that if I start watching any HDR content, it triggers a switch back to "Full" with no need to go into the Nvidia control panel!  No matter how it gets switched back to RGB full, it will stay that way as long as I'm actively using it, but if I ever switch the system off and come back a few hours later, it reverts to limited again.

This is driving me nuts.  Any ideas from anyone on how to resolve this permanently?  What am I missing or doing wrong?

It sounds like an oddity with the Nvidia video drivers.

I would either choose 8-bits for all refresh rates, which simplifies things and looks identical to 12-bits anyways. Or perhaps try using an EDID override, like described below, in the event this is related to an HDMI handshake issue when you turn on the AVR:

251833 (thread)

Thanks for the EDID override suggestion, hadn't really thought about it being a possible handshake issue.  I was really hoping that was it, but I finally got a minute to try it and unfortunately it didn't help, still getting the same behavior.  I reset all the refresh rates to 8-bits last night, so I'll check it out later and see if that fixes things.  Thanks again for the help and the guide.  I'll report back later. 

Still no luck.  Even set 8-bits across the board and EDID override in place, still (eventually) reverts to RGB limited after power off.  Anyone have any other suggestions/ideas?