So i ran into this issue as well. I started MM stuff 2-3 weeks ago.

When everything was working my logs show:

• I had the previous mm version ( probably 2.3.1)
• Enable the Open GL driver, fake KMS (via raspi-config)
• Disabling the screensaver https://www.raspberrypi.org/forums/viewtopic.php?t=57552
• Autohiding the Mouse Pointer
• rotate screen 270deg(CW), display_rotate=3 at /boot/config.txt
• I also had the dtoverlay=vc4-fkms-v3d line there
• I was getting this error though (thrunpm start ):

libGL error: MESA-LOADER: failed to retrieve device information
MESA-LOADER: failed to retrieve device information
MESA-LOADER: failed to retrieve device information

Anyway I messed something on my modules and had to reinstall the Raspbian. Same as before, Stretch 7/-18

• Rotate screen at /boot/config.txt
• installed the MM 2.4.1 and tried it straight away default config and modules. It was working alright
• Disabling the screensaver https://www.raspberrypi.org/forums/viewtopic.php?t=57552
• Autohiding the Mouse Pointer
• I think I added the dtoverlay=vc4-fkms-v3d line…
  • and boom animations started lagging (+high CPU)
  • also npm start dev didnt work. It launched but no mirror was shown and if i had mm running it would stop refreshing.

Any way I figured out that taking that commenting out that # dtoverlay=vc4-fkms-v3d everything works flawlessy. I dont get the “libGL”-error
and I also updated npm 5.6.0 → 6.2.0 sudo npm i -g npm and npm start dev started working (dev or no dev).

My Rpi temperature is under 50C when mm is running (no heatsink).

Hope this helps out someone!