I used rock pi 4b+ with android 11 system image. The system was on and display OK, then I left for a while. When I back displayer hinted “No signal”. I though might be sleep, hit the keyboad and mouse, still “No signal”.
Tried with serial console of ubuntu system on SD card, system was not damaged but still “No signal”, and came out with those related with HDMI:
[ 3.052221] vcc1v8_hdmi: supplied by vcc5v0_sys
[ 3.060470] vcc0v9_hdmi: supplied by vcc5v0_sys
[ 5.450971] dwhdmi-rockchip ff940000.hdmi: Detected HDMI TX controller v2.11a with HDCP (DWC HDMI 2.0 TX PHY)
[ 5.471729] rockchip-drm display-subsystem: bound ff940000.hdmi (ops dw_hdmi_rockchip_ops [rockchipdrm])
[ 5.678052] dwhdmi-rockchip ff940000.hdmi: PHY failed to power down
[ 15.211865] dwhdmi-rockchip ff940000.hdmi: PHY failed to power down
[ 42.969775] rc rc0: dw_hdmi as /devices/platform/ff940000.hdmi/rc/rc0
[ 42.969940] input: dw_hdmi as /devices/platform/ff940000.hdmi/rc/rc0/input5
related with drm:
[ 5.433436] rockchip-drm display-subsystem: bound ff8f0000.vop (ops vop_component_ops [rockchipdrm])
[ 5.435436] [drm] unsupported AFBC format[3231564e]
[ 5.458301] rockchip-drm display-subsystem: bound ff900000.vop (ops vop_component_ops [rockchipdrm])
[ 5.465838] rockchip-drm display-subsystem: bound ff940000.hdmi (ops dw_hdmi_rockchip_ops [rockchipdrm])
[ 24.123490] rockchip-drm display-subsystem: [drm] fb0: rockchipdrmfb frame buffer device
[ 24.140836] [drm] Initialized rockchip 1.0.0 20140818 for display-subsystem on minor 0
[ 28.261974] systemd[1]: Condition check resulted in Load Kernel Module drm being skipped.
Please help me, I have no idea O_o.