rockchip-drm display-subsystem: [drm] *ERROR* POST_BUF_EMPTY irq err at vp0

[Marcin Juszkiewicz]

I took my FriendlyELEC NanoPC-T6 LTS back to operation. Installed Fedora 
rawhide on it and trying to get screen working.

Running 6.14-rc6 on it. Kernel log is full of this message:

rockchip-drm display-subsystem: [drm] *ERROR* POST_BUF_EMPTY irq err at vp0

/sys/devices/platform/display-subsystem/drm/card0/card0-HDMI-A-1/modes 
shows list of resolutions available on my 10" screen. Monitor says 
"HDMI: no signal".

I remember having screen running once with some set of out-of-tree 
patches but iirc it was before HDMI0 support was present in mainline.

Where I should look?