Not getting 10 bit color on 6800 XT

Ask Fedora
1

Hi,

I m currently running fedora kde 42.

My issue is i m not getting 10 bit output.

I have a 6800xt AMD 5950x and is connected to sony A95L OLED TV.

On windows , no issue in getting 4k 120hz 10 bit rgb. But on fedora kde no luck at all.

I m connecting via hdmi 2.1 port and cable to my OLED TV.

I have also tried with a DP 1.4 → hdmi 2.1 adapter. still no luck.

On googling the issue, everyone says that KDE plasma 6 is supposed to automatically set the color depth to 10 if you hardware supports it. but its not.

My hardware supports it as is confirmed by windows.

I have also tried to force the edid , no luck. I can only change yuv or rgb via edid override. cannot override color depth via edid override.

2

What does kscreen-doctor -o report?
You should see info on HDR in the output.

3

OK i have gone back to 5700 AMD gpu but i m using DP 1.4 → hdmi 2.1 to get 4k 120hz 10 bit rbg which windows has no problem.
if i run screen-doctor -o without hdr enabled

Output: 1 DP-2
        enabled
        connected
        priority 1
        DisplayPort
        Modes:  1:3840x2160@60!  2:4096x2160@60  3:4096x2160@60  4:4096x2160@50  5:4096x2160@24  6:4096x2160@24  7:3840x2160@120*  8:3840x2160@120  9:3840x2160@100  10:3840x2160@60  11:3840x2160@60  12:3840x2160@50  13:3840x2160@30  14:3840x2160@30  15:3840x2160@30  16:3840x2160@25  17:3840x2160@24  18:3840x2160@24  19:1920x1200@60  20:1920x1080@120  21:1920x1080@120  22:1920x1080@100  23:1920x1080@60  24:1920x1080@60  25:1920x1080@60  26:1920x1080@50  27:1920x1080@30  28:1920x1080@30  29:1920x1080@24  30:1920x1080@24  31:1600x1200@60  32:1680x1050@60  33:1600x900@60  34:1280x1024@60  35:1440x900@60  36:1280x800@60  37:1152x864@75  38:1280x720@60  39:1280x720@60  40:1280x720@60  41:1280x720@50  42:1280x720@30  43:1280x720@30  44:1280x720@24  45:1280x720@24  46:1024x768@60  47:800x600@60  48:720x576@50  49:720x576@50  50:720x480@60  51:720x480@60  52:720x480@60  53:720x480@60  54:640x480@60  55:640x480@60  56:1600x1200@60  57:1280x1024@60  58:1024x768@60  59:2560x1600@60  60:1920x1200@60  61:1280x800@60  62:3840x2160@60  63:3200x1800@60  64:2880x1620@60  65:2560x1440@60  66:1920x1080@60  67:1600x900@60  68:1368x768@60  69:1280x720@60 
        Geometry: 0,0 3072x1728
        Scale: 1.25
        Rotation: 1
        Overscan: 0
        Vrr: incapable
        RgbRange: unknown
        HDR: disabled
        Wide Color Gamut: disabled
        ICC profile: none
        Color profile source: sRGB
        Color power preference: prefer accuracy
        Brightness control: supported, set to 100% and dimming to 100%

with HDR enabled

Output: 1 DP-2
        enabled
        connected
        priority 1
        DisplayPort
        Modes:  1:3840x2160@60!  2:4096x2160@60  3:4096x2160@60  4:4096x2160@50  5:4096x2160@24  6:4096x2160@24  7:3840x2160@120*  8:3840x2160@120  9:3840x2160@100  10:3840x2160@60  11:3840x2160@60  12:3840x2160@50  13:3840x2160@30  14:3840x2160@30  15:3840x2160@30  16:3840x2160@25  17:3840x2160@24  18:3840x2160@24  19:1920x1200@60  20:1920x1080@120  21:1920x1080@120  22:1920x1080@100  23:1920x1080@60  24:1920x1080@60  25:1920x1080@60  26:1920x1080@50  27:1920x1080@30  28:1920x1080@30  29:1920x1080@24  30:1920x1080@24  31:1600x1200@60  32:1680x1050@60  33:1600x900@60  34:1280x1024@60  35:1440x900@60  36:1280x800@60  37:1152x864@75  38:1280x720@60  39:1280x720@60  40:1280x720@60  41:1280x720@50  42:1280x720@30  43:1280x720@30  44:1280x720@24  45:1280x720@24  46:1024x768@60  47:800x600@60  48:720x576@50  49:720x576@50  50:720x480@60  51:720x480@60  52:720x480@60  53:720x480@60  54:640x480@60  55:640x480@60  56:1600x1200@60  57:1280x1024@60  58:1024x768@60  59:2560x1600@60  60:1920x1200@60  61:1280x800@60  62:3840x2160@60  63:3200x1800@60  64:2880x1620@60  65:2560x1440@60  66:1920x1080@60  67:1600x900@60  68:1368x768@60  69:1280x720@60 
        Geometry: 0,0 3072x1728
        Scale: 1.25
        Rotation: 1
        Overscan: 0
        Vrr: incapable
        RgbRange: unknown
        HDR: enabled
                SDR brightness: 500 nits
                SDR gamut wideness: 100%
                Peak brightness: 1671 nits
                Max average brightness: 1671 nits
                Min brightness: 0.0658 nits
        Wide Color Gamut: enabled
        ICC profile: none
        Color profile source: sRGB
        Color power preference: prefer accuracy
        Brightness control: supported, set to 100% and dimming to 100%

But my TV shows 8 bit when using linux.

On windows TV shows 10 bit color depth.

Edit: Now the TV is showing 10 bit color depth with and without hdr.

No idea what i did.

Case closed.

Update: I found out what i did to get 10 bit. I unplugged and plugged the hdmi cable to my adapter and that brought the 10 bit.
I found this by accident. Not in a million years i could have found this simple hack.
if anyone has this same issue, just unplug and plug the hdmi cable to the DP->HDMI adapter.

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