Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Tue, 12 Jul 2022 11:10:41 +0200 | Subject | Re: [PATCH 1/3] drm/fourcc: Add missing big-endian XRGB1555 and RGB565 formats |
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Hi Michel,
On Tue, Jul 12, 2022 at 11:09 AM Michel Dänzer <michel.daenzer@mailbox.org> wrote: > On 2022-07-12 11:03, Gerd Hoffmann wrote: > >>> As described above DRM_FORMAT_HOST_RGB565 means bigendian on bigendian > >>> hosts and little endian on little endian hosts. Which is not correct > >>> when your hardware does big endian no matter what. > >> > >> But (a) drm_driver_legacy_fb_format() uses DRM_FORMAT_HOST_RGB565 > >> if quirk_addfb_prefer_host_byte_order is set, > > > > Ah, right. Missed that in 'git grep' output. Given that traditional > > fbdev behavior is to expect native byte order using > > DRM_FORMAT_HOST_RGB565 there makes sense indeed. > > > > Scratch my comment about it being unused then ;) > > DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN is still what the driver should use conceptually, and should match DRM_FORMAT_HOST_RGB565 in drm_driver_legacy_fb_format on a big endian host (which is presumably always the case for the atari driver).
Sure, I'll update the patch accordingly.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
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
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