9060XT CachyOS Plasma RGB range setting not triggering TV auto adjustment

[nissel]

9060XT CachyOS kernel with stable patch applied, generally working really well but the RGB Range option in the KDE/Plasma Display Configuration is not triggering the correct HDMI metadata? infoframe? To switch the display into Full range mode.

My Samsung s90c stays in Limited mode, when Full is selected in Display Configuration resulting in an overly dark image and crushed blacks. I can manually set the display to Full but it would be good if Auto worked.

[adolfotregosa]

As far I can tell, it's not working correctly even on stock kernel, probably because my LG works in ycbcr in that case, not RGB.
On kernel 7.0-RC1 (hdmi_frl), in SDR, RGB Range actually works, in HDR it's stuck in Full.

EDIT: On hdmi_frl_stable, RGB Range also works in SDR, in HDR it's stuck in Full

[nissel]

I tried the AUR and got 7.0-RC1 (presumably mainline) also RGB range didn't work.

Then tried patching 6.19.3 via the cachyos kernel manager, without cachyos patches. RGB range didn't work.

Cachyos default kernel. RGB range does work.

[adolfotregosa]

This is a can of worms, honestly. From experience with AMD GPUs, they insist on using YCbCr over HDMI if the sink supports it, and the black level is limited in this case. RGB Range doesn't work in that scenario, it only works when the signal is set to RGB. With these patches, the signal becomes RGB on my LG. In SDR, RGB Range works, but in HDR, it becomes stuck in 'Full'.

[nazar-pc]

As far I can tell, it's not working correctly even on stock kernel

Not working for me with 7600 XT and Samsung QN990F with stable kernel either, no HDR involved.

I believe my previous TV Samsung QN800B didn't work correctly with Auto either. So this is not specific to changes in this repo. Though I do agree it'd be nice if it worked correctly.

[adolfotregosa]

Google says that the only known solution is to edit the EDID and remove YCbCr support. I tested it out, and it works. The moments during the boot process that previously used YCbCr are now in RGB Full range. HDR is still stuck in Full Range.