Hi Am 24.01.22 um 19:38 schrieb Geert Uytterhoeven:
Hi Daniel, On Fri, Jan 21, 2022 at 9:55 AM Daniel Vetter <daniel@xxxxxxxx> wrote:Just to clarify, since we had lots of smaller and bigger misunderstandings in the thread thus far: DRM_FORMAT_RGB332 exists, so drm support that already. The fbdev emulation doesn't yet, but all that's needed for that is filling out the code to remap the drm description to the fbdev format description for this case. Plus testing it all works ofc with fbcon and whatelse. Note that RGB332 is a bit more work than e.g. C4, since atm fbdev still uses only bpp to identify formats, so would need to be switch over to drm_fourcc first before adding anything which aliases with something existing (we have C8 already wired up).I doubt that RGB332 would be a bit more work than C4, as RGB332 is still 8 bpp, while C4 is less. To support C4, all DRM code that cannot handle format->cpp[0] < 1 or drm_format_info_block_width() > 1 has to be fixed first. On the plus side, I finally got my proof-of-concept Atari DRM driver working with fbcon on ARAnyM. Mapping /dev/fb0 from userspace doesn't work (fbtest SEGVs while reading from the mapped frame buffer). I don't know yet if this is a general issue without deferred I/O in v5.17-rc1, or a bug in the m68k MM code... So far it supports C8 only, but I hope to tackle C4 and monochrome soon. Whether the end result will be usable on real hardware is still to be seen, but at least I hope to get some DRM code written...
That sounds pretty cool. Best regards Thomas
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev
Attachment:
OpenPGP_signature
Description: OpenPGP digital signature
