Does anyone know if there is a way to disable the bilinear filtering when using the DRM/KMS driver with RetroArch on a RPi 3? I’ve tried setting scaling_kernel to 8 and it doesn’t seem to affect it.
I also need to know. Anyone here knows?
It’s not possible at the moment. I believe the problem is that the generic linux DRM interface doesn’t have a unified way of controlling filtering. It needs to be done in a device specific way, which would probably mean adding device specific code to RetroArch’s DRM driver and some sort of way to determine which hardware is in use (or control this at compile time).
The reason it works seamlessly with OpenGL on DRM is that there’s a hardware specific Mesa driver between Mesa and the DRM subsystem which handles this.
So, while it’s certainly possible to fix (although perhaps not in a “neat” manner), it’s a bit complicated and I wouldn’t hold my breath for a fix.
There was an option in retroarch to disable it. I remember doing so a couple of months ago but I’m not sure if it works in current git. Something like ‘hardware filtering’ or so in the menu.