No the debian drivers are installed they are just not that great. There is a MCU in the GPU called a Command Stream Frontend.
What we have and the way the kernel works is not doing that great a job as if we check
cat /sys/devices/platform/fb000000.gpu/utilisation you will prob find its only about 40%
Which is good and bad news as there is far more performance to be had but the drivers currently likely with the CSF are not acting like a asynchronous co-ordinator for cpu & gpu irq co-ord so they have some parallism as think cpu & gpu are acting synchronously.
The OpenCl methods seem to be better as if you use this as a base.
Then do a few hacks so we don’t have the cpu doing a lot of work whilst the gpu is running ML
Then via openCl cat /sys/devices/platform/fb000000.gpu/utilisation is about 75%