I have a Lenovo thinkpad T470s. When running Windows 10 pro 1709 the laptop outputs full 36bit deep color (12bpc) to the external monitor just fine.
When windows force updates to 1803, the thing only outputs 8bit.
My understanding is that this is driver related, since other users with simillar problems with discrete graphics got them sorted with updated drivers. Howerver this has not worked out for me in this case. How do I fix the problem.
Yes I tried. The machine was upgraded again to 1803 and again 10bit and 12bit is no longer possible although the graphics settings are set to equal as with 1709, including full quantization range and YCbCr enabled. Once windows updates to 1803 windows only outputs in 8bit mode. I reinstalled the Lenovo specific driver with no change. The generic driver does not finish installation complaining the system does not support the driver.
Because I made changes to the accounts of the system while in 1803, it is no longer possible for me to revert back to 1709 for 10bit color mode.
Thank you for your reply. I have done one better for you. I also have a X270 which is the same chipset and also equipped with the HD Graphics 620 which was fully updated, where I tried using the latest drivers supplied by lenovo. This machine did not output anything other than 8pbc regardless of what I tried. However, when completely reinstalling windows 10 Pro N 1709 from CD, this machine now outputs 12pbc just as the T470s did before it updated.
I have for the time being deactivated windows update because this is just frustrating and takes considerable time to debug. I however will run into other problems because windows will forcefully update eventually. I will try to upgrade to 1809 later on but i will use another drive and instance of windows for that testing purpose.
The thing I really want to know, is this a strategic move by Microsoft and/or intel to remove 10 and 12 pbc support from its drivers to force customers to upgrade their monitors to HDR-supported equivalents? Because with an updated Windows the HDR support seems to be the only method to achieve 10/12 pbc support. And regardles why is there no option in the driver to choose the bit depth of the resolution you chose just as with other "normal" drivers from say AMD?
HI Alberto. Sorry for the delay but I had my Intel forum login stored on another laptop which I haven't accessed in a few days.
This is some of the gear I can play around with and what I know.
I know this issue has been discussed in the past on other tech forums. The difference here is that I KNOW that the intel HD 620 is capable of outputing 12bpc because its doing it right now. It can be verified with the Pioneer control app. See attached image. As soon as I update windows 10 beyond 1709, the video input drops to 24bit which means 8 bits per channel.
Regarding the color depth within the apps. It doesn't matter what color depth the app is capable of producing if the screen mode is not already established in windows because the relevant applications as for example Photoshop or Lightroom are windowed within windows. Its commonly known that to work with whatever graphics that might cause banding effects, the screen display mode color depth has to be set which for both the quadro and the old Radeon 6450 is clearly and easily done with a switch within their respective driver software.
Also, in windows - settings - display, once updated beyond 1709 there is an option called "advanced display settings". Clicking on that one shows the display information per screen, and for the X270 as well as the T470s says its 8-bit regardless of the color format or any other available setting that I can find. However, in 1709 this option does not exist but the display bit depth through HDMI is clearly 12-bit both in RGB and in YCbCr
Personally, I cannot understand why there is no option to manually set the color depth if the Intel HD Graphics 620 clearly is capable of throwing out 12bpc. The only reasonable explanation is that Intel and/or Microsoft is driving the transition (and thus participating in a marketing strategy) towards HDR supported monitors. Is this the case? Can I change the color depth manually somehow? Or am I simply missing something?