Re: [PATCH v3 00/10] drm: Add support for low-color frame buffer formats

Sam Ravnborg
2022-07-09T13:39:37Z

Hi Geert,

On Fri, Jul 08, 2022 at 08:20:45PM +0200, Geert Uytterhoeven wrote:
> Hi all,
>
> A long outstanding issue with the DRM subsystem has been the lack of
> support for low-color displays, as used typically on older desktop
> systems, and on small embedded displays.

IT is super to have this addressed - thanks!

>
> This patch series adds support for color-indexed frame buffer formats
> with 2, 4, and 16 colors. It has been tested on ARAnyM using a
> work-in-progress Atari DRM driver supporting 2, 4, 16, 256, and 65536
> colors, with text console operation, fbtest, and modetest.
>
> Overview:
> - Patch 1 introduces a helper, to be used by later patches in the
> series,
> - Patch 2 introduces a flag to indicate color-indexed formats,
> - Patches 3 and 4 correct calculations of bits per pixel for sub-byte
> pixel formats,
> - Patches 5 and 6 introduce the new C[124] formats,
> - Patch 7 fixes an untested code path,
> - Patch 8 documents the use of "red" for light-on-dark displays,
> - Patches 9 and 10 add more fourcc codes for light-on-dark and
> dark-on-light frame buffer formats, which may be useful for e.g. the
> ssd130x and repaper drivers.

Applied all patches to drm-misc (drm-misc-next), including the last two
RFC patches as we then have the formats ready when a user pops up.

Sam