Raspberry Pi 5 LXQt DPMS not working

[unformatted]

I have LXQt running with linux-rpi aarch64 on RPi4 and just did a full upgrade. When I insert the sdcard in my new RPi5 and power up, it boots but hangs at "reaching target graphical interface".

From raspberry pi forum make_clickable_callback(MAGIC_URL_FULL, ' ', 'https://forums.raspberrypi.com/viewtopic.php?t=358853&hilit=MatchDriver+%26amp%3Bquot%3Bvc4%26amp%3Bquot%3B&sid=ed4956f69e8112b8cef732c090493b63', '', ' class="postlink"') it says to create an Xorg configuration file as follows:

/etc/X11/xorg.conf.d/99-vc4.conf
Section "OutputClass"
Identifier "vc4"
MatchDriver "vc4"
Driver "modesetting"
Option "PrimaryGPU" "true"
EndSection

This actually works, I'm now booting into LXQt (using sddm with autologin).

On RPi4 I am able to shut down my monitor immediately using "sleep 1 && xset dpms force off" but on RPi5 this does not work. Entering the command from qterminal the monitor blanks and briefly shows "No Signal Detected" every 7 seconds or so, but the monitor remains on.

I also tried linux-rpi-16k but same result.