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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 (Kernel Mode Setting) has two different implementations. The old one (known as Fake KMS) was the only one available at the time of Debian 9 Stretch and it is provided byt the vc4-fkms-v3d overlay. Once loaded you can check its availability reading the following pseudofile (should read disabled or okay):
cat /proc/device-tree/soc/firmwarekms@7e600000/status
The new overlay vc4-kms-v3d doesn't expose that node (which results as disabled), but expose several others KMS related nodes:
cat /proc/device-tree/soc/hdmi@7e902000/status cat /proc/device-tree/soc/hvs@7e400000/status cat /proc/device-tree/soc/txp@7e004000/status cat /proc/device-tree/soc/pixelvalve@7e207000/status cat /proc/device-tree/soc/pixelvalve@7e807000/status cat /proc/device-tree/soc/pixelvalve@7e206000/status