Hello Thomas, On Wed, 3 Dec 2025 10:40:17 +0100, Thomas Zimmermann <[email protected]> wrote:
> [2] > https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next-2025-12-01-1/drivers/gpu/drm/ast/ast_mode.c?ref_type=tags#L559 > [3] > https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next-2025-12-01-1/drivers/gpu/drm/ast/ast_cursor.c?ref_type=tags#L209 > > > + case DRM_FORMAT_RGB565: > > + ast_set_index_reg_mask(ast, AST_IO_VGACRI, AST_IO_VGACRA2, 0x3f, > > 0x40); > > + break; > > + case DRM_FORMAT_XRGB8888 While working on it I discovered that the Big-Endian byte-swapping bits do apparently not just-work on a newer AST2400 in our Power 8 while my initial patch did work as tested with an AST2200 in the Sun T4-1 :-/ Maybe that is what Timothy meant with "This is due to a ppc64 hardware quirk, which when combined with a hardware design fault in the AST2500 VGA controller results in a need to use software-based red-blue channel swapping." [1] Is there a way to simply specify the frame-buffer as BGRX8888? In a quick test the drm layer complaint about "not supported" and "no compatible format found"? Thanks, René [1] https://lore.kernel.org/dri-devel/407388289.1798972.1760725035958.javamail.zim...@raptorengineeringinc.com/ -- René Rebe, ExactCODE GmbH, Berlin, Germany https://exactco.de • https://t2linux.com • https://patreon.com/renerebe
