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EasyOS using VC4 graphics acceleration on Pi4

January 13, 2021 — BarryK

I posted about very sluggish video rendering, that was fixed by commenting out a line in 'config.txt':

That line "dtoverlay=vc4-fkms-v3d" was the culprit. Xorg used the 'modesetting' driver, which in turn causes Xorg to render via mesa DRI software renderer, /usr/lob/dri/ Which accounts for the slowness.

Commenting-out that line in 'config.txt' causes Xorg to load the 'fbdev' (frame buffer) driver. This gave quite snappy desktop rendering, however it will fall down when rendering games and video.

The solution was to recompile 'mesa' with the '' driver, which sits at /usr/lib/dri. I mentioned in a previous post that I had recompiled everything in OE for a generic aarch64 target CPU, armv8-a+crc. This compiled mesa without VC4 driver.

However, I had previously compiled in OE for a rpi4 target, and that has the driver. So, have created a PET just with that driver.

All that is required is to include /usr/lib/dri/ in the build, and enable that line "dtoverlay=vc4-fkms-v3d" in 'config.txt', and hey presto, fast screen rendering. Tried glxgears, looks good. 

Tags: easy