For a project, I need the Linux desktop to be set to 16 bits per pixel. I can't find any documentation about how to do this on the mainline kernel. Anyone?

3 hours ago, Larry Bank said:

For a project, I need the Linux desktop to be set to 16 bits per pixel.

That format is not yet supported by mainline driver (http://elixir.free-electrons.com/linux/latest/source/drivers/gpu/drm/sun4i/sun8i_layer.c#L64). Fortunately, it is easy to add support. In the aforementioned array add DRM_FORMAT_RGB565 and here http://elixir.free-electrons.com/linux/latest/source/drivers/gpu/drm/sun4i/sun8i_mixer.c#L69 add:

case DRM_FORMAT_RGB565:
		*mode = 10;
		break;

Currently I'm working on a improved DE2 DRM driver, which will include this.

 

However, I'm still not sure how to make that default choice. But first it must be supported by the driver

Thanks for the info. I have no idea how to modify/integrate the driver changes into my setup. I can work around the issue for now (with a performance hit), but it's good to know it will eventually be resolved. Eventually I guess I need to build Armbian from source so that I can experiment with things like this.