Bare metal, Assembly language • RPi5 Framebuffer

Hello all, I am currently trying to port my OS from QEMU to actual hardware (yay!) and am having some issues with requesting a framebuffer for the Raspberry Pi 5. As I understand it, the mailbox system referenced here is essentially gutted in favor of the way Linux does things. However, I have also seen that there are, potentially, some leftover framebuffer things that exist still for testing/debug purposes, as per the following two links:

viewtopic.php?p=2229354
https://github.com/raspberrypi/firmware/issues/1904

For my purposes, I simply need to be able to call a framebuffer and print to the screen. I have consistently received a response of 0x80000001 when I am attempting to allocate the framebuffer and I am unsure if this is due to an incorrect request (doubtful, since I have yoinked working code from others to test with) or because of some strange interaction between the leftovers of an old system and my current setup. Does anyone have any insights as to whether

A) I can get this working and/or
B) This is the best bare metal method of quickly and easily playing with a framebuffer-like object for the RPi5 and/or
C) I am barking up the right tree?

Thanks and please let me know if I need to provide any additional information

Statistics: Posted by DocumentationPolice — Tue Dec 03, 2024 8:44 pm

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