Intel Active Contrast (DPST) driving me nuts.
Hopefully anyone running across my issue is already semi familiar with the term. DPST (Display Power Saving Technology) or called Active Contrast by some is a power saving technology Intel has been implementing / continuing to improve since before 2007 in laptop displays to save power. (http://www.ruf.rice.edu/~mobile/elec518/readings/display/intel07.pdf , https://en.wikipedia.org/wiki/Intel_Display_Power_Saving_Technology)
My brand spankin’ new Dell Inspiron 7370 laptop that I just purchased in January has had this annoying problem since day 1. Due to a bad charge controller on the motherboard, I ended up getting a 2nd 7370, so I’ve also now had two machines, that both did / do the exact same thing.
If you’re still not familiar with what DPST does, it’s a little hard to explain. The best I can do to summarize, is that its “color sensitive brightness control” based on screen content. So, if you’ve got more dark colors of your window / desktop whatever you’re looking at, the display dims. If you’ve got lighter colors, it brightens. It’s actually sort of the opposite of what you’d think, because it ends up blinding the user when you get a nice white page like google search landing page, and the whole screen lights up; to squinting when you hit bing’s search page, which almost always has a really good looking photo of some trees or water, both of which are darker, causing the entire screen to dim, and text to get really hard to see until your eyes adjust.
And yes, I’ve worked with Dell for over a month, we’ve tried every single thing through Windows you can to turn off any power saving, auto-dimming or auto brightness, or adaptive brightness, etc that there is at least three times. Dell says they’ve escalated it to their engineering (read, development) department, but I’m not convinced they know what is going on, either. I also made a video of my duplicating the problem (Dell tech support India called it “strobe lights / club on a computer”) which you can watch here:
I specifically focus on the clock/address in the tray / notification area because to me, I cannot see any reason why that should change based on what is happening with regards to screen colors. You’ll see me fairly rapidly alt-tabbing between a light full-screen window, and a dark one. Notice how long it takes my iphone to adjust to the light difference!
I’m not the first to have this problem, its gone on for ages. Different laptops, different people. They’ve all eventually done one of two things. A) Done something to get the option to show up in the intel graphics control panel to “turn off adaptive” or “full performance” instead of “balanced” for display, or B) a registry modification. I’m looking for B, because I’ve done A, and it hasn’t helped. Heres some more articles on others that have had the problem, and what they did to fix it (I’ve also attempted to do everything they have, which is why I included the links)
Please place an X to the right of the option showing how often you see this issue using specific steps. (Ex: 'Every few times a game is started it flickers.' <- This would be "Often")
Always (100%): X
Very Sporadic (<20%):
Brand and Model of the system.
Dell Inspiron 7370
Hybrid or switchable graphics system?
ie Does it have AMD or NV graphics too?
No, native Intel UHD 620 Graphics adapter
Make and model of any Displays that are used to see the issue (see note2 below).
LFP = Local Flat Panel (Laptop panel) N/A
EFP = External Flat Panel (Monitor you plug in) N/A
How much memory [RAM] in the system (see note2 below). 16GB
Provide any other hardware needed to replicate the issue.
ie: Cables&brand, cable type [vga, hdmi, DP, etc], dock, dongles/adapters, etc N/A
Hardware Stepping (see note1 below). N/A
Operating System version (see note2 below). Windows 10 Pro v10.0.16299 Build 16299
VBIOS (video BIOS) version. This can be found in “information page” of CUI (right click on Desktop and select “Graphics Properties”.
Driver Version: 220.127.116.1177
Graphics Driver version; for both integrated Intel and 3rd party vendors (see note2 below). N/A
SW or Apps version used to replicate the issue. A dark window and a light window.
Single display, clone, or extended (see note2 below). N/A - Single
Display resolution & refresh rate setting of each display (see note2 below). 1920x1080 @ 60hertz
AC or DC mode, i.e. is power cable plugged in or not? ONLY DOES WHEN NOT PLUGGED IN (BATTERY) – SWITCHING TO PLUGGED IN MAKES PROBLEM DISSAPEAR.
How to repro
Please provide steps to replicate the issue. These steps are very crucial to finding the root cause and fix.
A screenshot to illustrate the issue is a huge plus. A video of the failure is even better! Attach to the post or provide the YouTube link.
I’ll repost the link https://www.youtube.com/watch?v=8vC4tREV1z4
So, before you say “its your power profile!” – I built a brand new one, and checked all the display configs and set everything to high performance, or disabled for any graphics power saving related features. (Dell also did this about three times or so). Sorry. Not the issue. Also tried the “high performance mode” which is only accessible through the Dell quickset tool where they’ve hidden away the “high performance” mode, which also makes no difference.
Dell has been working on this for going on two months now. I contacted Intel support about two weeks ago, and they’ve now given up and kicked it over to you, the Intel community. So you guys, are literally, my last hope.
Someone, please tell me, where in de hell the damn reg key to turn off this bloody DPST when its on battery power is. I’ve messed with the featuretestcontrol reg key (no difference), I’ve located and changed the value of every reg key with the word “power” in it under the
Directory so the “dcpowerprofile” matches the same value as the “acpowerprofile” – no dice. I’ve rolled back drivers, updated drivers. Yes, all the dumb little auto-brightness-sensor this through windows (or services) has been turned off, or disabled, so there, I’ve said it. Again – Dell has had their lvl 1 and lvl 2 techs on this machine on at least 6 remote sessions. Some of them have been for 4-6 hours.
I know there’s a reg key I can change. I just don’t know where. I did download proc monitor and ran it and isolated the processes for intel, but let me tell you, its accessing a ton of paths/keys. I also remember process monitor being a lot more useful… It doesn’t even give the key name now, just the directory. Maybe I haven’t played with it enough.
Your help is greatly appreciated, in advance!