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[SOLVED] No HDR option in Bazzite/KDE after connecting computer directly to display

I am running Bazzite 40 on a system with an RTX 4080. Up until yesterday, I was connecting computer -> Samsung HW-Q900C soundbar -> Samsung Q90C TV. I learned that the soundbar doesn't have HDMI 2.1 ports which is why I hadn't been able to get 120Hz, so I changed my setup to computer -> TV + soundbar -> TV (eARC).

Now, I do have 120Hz, but I lost a bunch of other options in my display settings, including HDR. The only options I can set there now are resolution, orientation, refresh rate, and scale. I suspect this is an issue with the TV communicating its capabilities in a way the OS doesn't understand, but I'm not sure how to fix or work around it. Can anyone suggest a fix? Is there a setting I can change on the TV or maybe an app I can run on the computer to manually set the TV's capabilities?

Update: Just discovered kscreen-doctor. Here's the output:

 undefined
    
Output: 445 HDMI-0
    enabled
    connected
    priority 1
    HDMI
    Modes:  446:3840x2160@60!  447:4096x2160@120  448:4096x2160@100  449:4096x2160@60  450:4096x2160@50  451:4096x2160@30  452:4096x2160@24  453:4096x2160@24  454:3840x2160@144  455:3840x2160@120*  456:3840x2160@100  457:3840x2160@60  458:3840x2160@50  459:3840x2160@30  460:3840x2160@25  461:3840x2160@24  462:3840x1600@144  463:3840x1600@120  464:3840x1600@60  465:3840x1080@144  466:3840x1080@120  467:3840x1080@60  468:2560x1440@120  469:2560x1080@144  470:2560x1080@120  471:2560x1080@60  472:1920x1080@144  473:1920x1080@120  474:1920x1080@100  475:1920x1080@60  476:1920x1080@60  477:1920x1080@50  478:1920x1080@30  479:1920x1080@25  480:1920x1080@24  481:1680x1050@60  482:1600x900@60  483:1440x900@60  484:1280x1024@75  485:1280x1024@60  486:1280x800@60  487:1280x720@60  488:1280x720@60  489:1280x720@50  490:1152x864@75  491:1024x768@75  492:1024x768@70  493:1024x768@60  494:800x600@75  495:800x600@72  496:800x600@60  497:720x576@50  498:720x480@60  499:640x480@75  500:640x480@73  501:640x480@60 
    Geometry: 0,0 3840x2160
    Scale: 1
    Rotation: 1
    Overscan: 0
    Vrr: incapable
    RgbRange: unknown
    HDR: incapable
    Wide Color Gamut: incapable
    ICC profile: incapable
    Color profile source: incapable

  

SOLUTION: Turns out this was my goof. I was trying to set up auto-login on my user account. In doing so, I set it to automatically log in to Plasma (X11) instead of Plasma (Wayland). Odd that the default option in that dropdown is not the one you’re currently using, but 🤷‍♂️.

What I’m now trying to figure out is why I can’t set auto-login for Plasma (Wayland). The Apply button is disabled. 🤔

Thanks to everyone who shared ideas.

9 comments
  • The monitor isn't capable of HDR. Maybe check your monitor settings

    • The monitor definitely is. Like I said, it was working when connected through the soundbar. It seems to be that it isn't reporting capabilities the same way the soundbar did when connected directly to the computer.

      • What I am saying is that I don't think this is a software issue. It sounds like something changed that caused it to lose support.

  • Things to try: a different brand cable, an hdmi-switcher.

    • HDMI switcher is an interesting idea. Will it do more than just forward on the EDID? (Hope I have that right. 😅) Will it sorta translate it and push out its own EDID?

      The cable is one of the two cables that previously completed the chain between the display and computer. Could it still be a problem in spite of that?

9 comments