there is no real "gpu memory"I want to know how to access GPU memory, VPU, QPU, and registers without mailbox interface.
the arm has direct access to all ram, and the v3d core on the pi4 goes thru a custom MMU that maps a 4gig virtual space onto the physical space with all ram
the arm core can also freely access the v3d and manipulate the QPU as it wishes, the pi4 firmware has no v3d support, so linux is in control of that normally
so that just leaves the VPU, which can only be controlled using the mailbox when on the official firmware
https://github.com/raspberrypi/firmware ... ecute-code
Statistics: Posted by cleverca22 — Thu Jan 15, 2026 5:32 am