24-bit or 32-bit framebuffers

Norman Feske norman.feske at ...1...
Fri Feb 16 09:40:13 CET 2018

Hi Ben,

On 14.02.2018 09:46, Nobody III wrote:
> Genode's Framebuffer session interface seems to only support 16-bit
> color. Why don't we have support for 24-bit or 32-bit color? Even VESA
> supports 24-bit color, so it seems like adding driver support is likely
> trivial.

for our use cases so far, RGB565 was sufficient. In components like
VirtualBox5 or our custom GUI components (menu_view, launchpad), the use
of dithering reduces the visible effect to an acceptable level. We
sticked to RGB565 to conserve memory and pixel-copy bandwidth. This
seemed like an important consideration 10 years ago when we started -
but much less so today.

We plan to switch to 32-bit color over the course of this year.

The change is not trivial though. We will need to adjust and test all
framebuffer drivers (looking at the various ARM boards), and adjust all
components of the GUI stack (nitpicker, nitpicker clients, etc.).

We won't offer options for pixel formats. Once we switch to 32-bit,
RGB565 won't be available anymore.


Dr.-Ing. Norman Feske
Genode Labs

https://www.genode-labs.com · https://genode.org

Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden
Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth

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