Idea for Nvidia GPU on CM4

[iAmInActions]

How I got this Idea
I have used other arm-based machines before and most had problems with proprietary drivers under debian and arch.

What I did to solve it
I installed a copy of Ubuntu Server 20.04 aarch64 and installed gdm3 and lxde to get a grafical user interface. Then I installed software-properties-gtk, started it and went to the advanced driver section. There I installed all drivers that were not working before. Then I closed it, updated the initramfs and rebooted. Usually, it worked after that. Sometimes I had to compile a newer kernel to get it to work.

Why can't I try it on my own pi?
I don't own a CM4 or a modded pi 4 so it would be nice if someone who owns one could try this for me. All feedback is appreciated.

[paulwratt]

sounds fesible (in theory), but some of the issue that have com up so far require tweeking source:

• MSI Mode compatibility is not 100%
• there are issues with "plain" 64bit-write-combined functions, and reworking is needed of read-combined functions
• most memio functions are broken, mostly due to the above
• as a result, RPi CM4 PCIe is not 110% out-of-the-box, more like 95-98% (97% ?) (at least for graphics cards)

there is lots of technical details in #4 (HD5450) when @Coreforge start his work.
outside of graphics cards, it seems to depend on how the drivers were written, as a lot seem to work with only a kernel option needing to be enabled (I can see a kernel8-cm4.img being a default in future releases at some point, with all useful aarch64 PCIe related kernel settings enabled - see the Intel 2.5Gb network card and the 16 drive NAS videos for references)

[FreddyFeuerstein]

Maybe compiling buildroot for the pi but with the aarch64 server flags set could configure the bus correctly. It would be a ton of work bc you would have to cross-compile a small but still complex operating system. And seeing as it took me 2 whole days to get buildroot working on a usb drive to rickroll friends with it, it would probably take around a week to get it set up.

Edit:
Will 118% try this once i get my hands on a modded pi 4 or a cm4.

[paulwratt]

there are some distros for RPi that use buildroot, there should be (by now) one for RPi3/4 (aarch64), if so, a delve into their configs would proove worthwhile.

For anyone going as far to get a (clean) aarch64 buildroot for RPi4/3 you might also (or alternatively) try mkroot and include the work done from qemu-rpi-kernel to get everything working on host OS first (presuming there is RPi3/4 emu - see native-emulation directory)

If nothing else it will get a extremely small (memory footprint) environment running on RPi (as it uses ToyBox suplimented by BusyBox).

Cheers
Paul
PS. both of these are on my (no lengthy) TODO list, as soon as I get stable power, and replace/fix my failing 4G RPi4 (mHDMI port).

[FreddyFeuerstein]

[...]
For anyone going as far to get a (clean) aarch64 buildroot for RPi
[...]

I already have a working config for buildroot with X11, twm and rpm. Would just have to recompile it for aarch64 with uefi, put the boot loader and the os on a usb drive and it should work.

[FreddyFeuerstein]

Ill buy a cm4 once they are available again in my country. I want to try both methods.

[geerlingguy]

Going to move this to a discussion, since it's a little more of a conversation and less actionable.