This is an old revision of the document!
Table of Contents
Graphics hardware acceleration on the Raspberry Pi 2
In this article we will discover how to enable graphics hardware acceleration in the Chromium browser running on the Raspberry Pi 2, using RaspiOS based on Debian Bullseye 11.
The hardware model si Raspberry Pi 2 Model B Rev 1.1 (ARMv7 Processor rev 5, v7l), the operating system is RaspiOS based on Debian 11.5 Bullseye, the architecture is armhf (32bit), the running kernel is 5.15.61-v7+.
How to check if V3D and/or KMS are active
V3D is an API provided by the Linux kernel to support 3D graphics on the VideoCore VI GPU (RPi 4). The software driver is actually provided in the form of a Device Tree Overlay which is loaded at boot time adding the following line into /boot/config.txt:
dtoverlay=vc4-kms-v3d
The older Raspberry Pi 3 and Pi 2 have the older VideoCore IV GPU and the legacy software driver was called VC4. The new Device Tree Overly is capable to detect the actual VideoCore available (IV or VI) and provide the same new V3D interface.
To check if V3D is enabled you can read a /proc pseudofile, the content of which can be okay or disabled. For the Raspberry Pi 3 it is:
cat /proc/device-tree/soc/v3d@7ec00000/status
For the Raspberry Pi 4 the exposed pseudofile is different:
cat /proc/device-tree/v3dbus/v3d@7ec04000/status
The KMS driver (Kernel Mode Setting) results disabled when you load the new vc4-kms-v3d overlay. You can check the following pseudofile:
cat /proc/device-tree/soc/firmwarekms@7e600000/status
Is OK to have it disabled? What to do to have it enabled?
To get that pseudofile reading okay on the Raspberry Pi 2, I discovered that it is possibile to load the obsolete Fake KMS overlay, named vc4-fkms-v3d. The older overlay were required e.g. by the RaspiOS based on the old Debian 9 Stretch, but the software implementation in that driver is not as good.