[PATCH] handle 10-bpc framebuffer layouts

[PATCH] handle 10-bpc framebuffer layouts

[Pip Cet]

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I'm playing with barebox on an Apple M1-based MacBook Pro that uses
the (new-ish) x2r10g10b10 framebuffer layout. The attached patch is
sufficient to get a white-on-black prompt rather than black-on-black
text.

(I can't actually use the prompt yet, as there's no keyboard driver,
but it's a start.)

I'm aware that this code isn't as accurate as it could be (the LSBs of
the 10-bit color are always 00), but I think it's worth it to keep
this code (relatively) simple, and the difference is unlikely to ever
be apparent to anyone. Please let me know if you'd prefer a version
which does the (r * 0x101) >> (16 - length) thing or any other
version.

Thanks!
Pip

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From eac9610833b747aa3d1685dbc665cf13d863eaa6 Mon Sep 17 00:00:00 2001
From: Pip Cet <pipcet@gmail.com>
Date: Sat, 5 Jun 2021 19:59:09 +0000
Subject: [PATCH] graphic_utils.c: handle 10-bpc framebuffer layouts

Signed-off-by: Pip Cet <pipcet@gmail.com>
---
 lib/gui/graphic_utils.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/gui/graphic_utils.c b/lib/gui/graphic_utils.c
index 0bed93221..3cb791050 100644
--- a/lib/gui/graphic_utils.c
+++ b/lib/gui/graphic_utils.c
@@ -24,10 +24,10 @@ u32 gu_rgb_to_pixel(struct fb_info *info, u8 r, u8 g, u8 b, u8 t)
 {
 	u32 px;
 
-	px = (t >> (8 - info->transp.length)) << info->transp.offset |
-		 (r >> (8 - info->red.length)) << info->red.offset |
-		 (g >> (8 - info->green.length)) << info->green.offset |
-		 (b >> (8 - info->blue.length)) << info->blue.offset;
+	px = ((t << 2) >> (10 - info->transp.length)) << info->transp.offset |
+		((r << 2) >> (10 - info->red.length)) << info->red.offset |
+		((g << 2) >> (10 - info->green.length)) << info->green.offset |
+		((b << 2) >> (10 - info->blue.length)) << info->blue.offset;
 
 	return px;
 }
-- 
2.30.2


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