f.lux unwanted dimming of display on desktop PC, and leaving it dimmed when disabled, and even when quit.



  • I have been an F.lux user since the early days, and really like the product, but have been experiencing some issues lately that I thought I should report.

    I am running Windows 10 Home x64, latest version (Nov 2019).

    My system is an older one, but pretty vanilla:
    Asus motherboard P7P55D-E PRO
    Intel Core-I7 860
    8gb ram
    NVIDIA GeForce GTX 1060 3GB display adapter running in 4k HDR (60hz refresh) mode connected via HDMI to a 55" TCL 55P605 TV
    (latest non-beta version of Nvidia drivers installed)

    Here's what happened:
    Over the past few weeks I have noticed that the screen seems noticeably dimmer. Just prior to my upgrading to the November windows 10 feature update, it was so dim that I could hardly read it. I figured that something might have corrupted the system, so I installed the November update, and it was better.

    However, it still was dimmer than I liked. I tried using the ALT-pageup shortcut to make sure that f-lux hadn't dimmed the display, and the notification came up saying it was at full brightness. I went into the Nvidia settings, and tried to adjust the settings there -- specifically the brightness setting. I had to deselect the "let other programs control the settings" button to attempt this. When f.lux wasn't disabled, the settings would briefly take effect until I took my finger off the mouse button and then the brightness would reduce again. Okay, so I figured that f.lux was controlling things, so I "disabled" f.lux for an hour and again attempted to change the brightness in the nvidia settings. This time it seemed to hold after I released the mouse button, BUT, when I went to any other window on the desktop, suddenly the brightness again reduced. The warmness of the color didn't change, but it re-dimmed.

    This seemed pretty strange behavior, but I then decided to actually exit f.lux instead of disabling it. The screen still remained dimmed, but then I changed the brightness in the nvidia control panel again. This time it stayed bright.

    So, the culprit does seem to be f.lux. F.lux is doing something to the system that is effecting the brightness of the display, and is not reversing its changes when it is disabled. Even worse, when the program is exited, the changes remain until they are forced to be "fixed" by modifying the brightness settings in the nvidia settings. f.lux IS changing the "warmness" of the display back from the warmer color palette to the cooler palette, but not the brighness.

    Also, it seems a bit strange that f.lux is doing much to the brightness at all when I haven't used the ALT-pagedown to request dimming.

    BTW, I wondered if there might possibly be some new communication protocol I wasn't aware of that might actually be allowing the display adapter to modify the brightness on the TV via the HDMI cable. I confirmed by going into the TV menus that this wasn't the case.

    Remember that this is a "desktop" -- not a laptop PC. There are NO brightness controls within windows itself for desktop machines, because the backlighting of the display (in this case my 4K HDR TV) is controlled on that external device. There also is no adaptive brightness option for the same reason.

    I have carefully gone through all running programs and services to verify that they don't have some way or option to modify the display, and they don't. There aren't any strange remnants of other video drivers left either. I used the ATI removal tool to force all remnants of the old display driver to be removed when I upgraded to the new Nvidia card..

    So, how do I work with you folks to get you the information you need to track down this bug? Screen shots probably won't show the difference between the dimmed, but not otherwise modified display (no white warmness modification) when f.lux is "disabled" vs. the brighter display when f.lux isn't running.

    I hope to hear back from you folks soon. Feel free to contact me at my email address that you have on file directly if you need to.

    Thanks,

    Philip
    P.S. forgive me if this gets posted twice. The first time I tried to post it, it didn't show up on the forum -- maybe there is a delay and this will show up twice. If so, please remove the first one.



  • First can you post f.lux options > driver info?

    Second, this could possibly be a monitor profile, but we'll be able to tell that after you post the driver info.



  • here it is -- this is with f.lux running using the "reduce eyestrain" setting during daylight hours (5900k) :
    NVIDIA 26.21.14.4120: NVIDIA GeForce GTX 1060 3GB (20191106)

    Generic PnP Monitor, 800 x 450mm, built 2017
    Chromaticities:
    R=0.642578 0.332031
    G=0.322266 0.623047
    B=0.146484 0.055664
    W=0.280273 0.290039
    sRGB gamut: 95%, AdobeRGB gamut: 66%

    Monitor 1 on NVIDIA GeForce GTX 1060 3GB: VCGT=0 gamma=1

    Windows Build: 18363.476



  • @herf said in f.lux unwanted dimming of display on desktop PC, and leaving it dimmed when disabled, and even when quit.:

    First can you post f.lux options > driver info?

    Second, this could possibly be a monitor profile, but we'll be able to tell that after you post the driver info.

    Hi Herf,

    I posted the information you requested.

    Any ideas on what is causing this issue?

    Please advise,

    Philip



  • First question is: do you have HDR turned on in Windows?

    We are investigating the new HDR support on NVIDIA in the latest drivers, but it does seem to behave quite differently than the normal color controls.



  • @herf said in f.lux unwanted dimming of display on desktop PC, and leaving it dimmed when disabled, and even when quit.:

    First question is: do you have HDR turned on in Windows?

    We are investigating the new HDR support on NVIDIA in the latest drivers, but it does seem to behave quite differently than the normal color controls.

    Yes, that is the entire reason I upgraded my video card was to enable 4K with HDR on my 55" TCL 4k HDR TV, and also to comply with the latest hdmi digital protection scheme so I could stream 4k HDR video.

    My computer serves a dual function -- it is my main PC for email, browsing, and office apps, but it also serves as my livingroom media PC.

    "smart" TVs just aren't smart enough to do what I need on the media side of things....

    I also have to say that having a video card capable of 4k made a dramatic improvement in the clarity and definition of my use of this 4k hdr tv as a monitor for my day-to-day desktop pc usage too. While some folks say you cannot tell the difference between 1080p and 4k from a distance of 11 feet, I strongly disagree, as will I think anyone who is able to switch to the higher resolution. Of course, HDR makes a tremendous difference when watching media....

    Please let me know if you need anything else from me. I am a retired programmer/analyst and would be happy to provide whatever feedback or testing support I can in support of your f-lux efforts.... Feel free to contact me via the email address you have on file if you need to.

    Philip



  • @herf said in f.lux unwanted dimming of display on desktop PC, and leaving it dimmed when disabled, and even when quit.:

    First question is: do you have HDR turned on in Windows?

    We are investigating the new HDR support on NVIDIA in the latest drivers, but it does seem to behave quite differently than the normal color controls.

    @herf, did you get the private message I sent last week that the brightness seems to have resolved itself? I asked if you had done something to F-lux that might have corrected the brightness issue, but got no reply.

    At this time it seems to be behaving itself again, with the <alt><pgdwn> and <pgup> working properly in HDR mode. I am going to try doing an dimming and then suspending the program and see what happens.

    Results of that testing:
    Disabling for an hour worked, and the brightness and color came back up.
    Exiting f-lux also worked properly, with the brightness and color being reset to default values immediately.
    restarting f-lux went properly as well, with the slow color change and the <alt><pgdwn> and <pgup> working properly again.

    I have not installed any new drivers since I reported the incident last week, nor any windows updates. Have you folks updated something?

    Please advise,

    Philip


Log in to reply