From d237f719b2726c0e6d62bfa1543f53b624471929 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Tue, 28 Apr 2026 10:28:43 +0200 Subject: [PATCH] lib/fonts: Fix bit position when rotating by 180 degrees MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix the horizontal bit position when rotating a glyph by 180°. The original code in rotate_ud() rounded the value in width up to a multiple of 8, aka the bit pitch, and calculated the rotated pixel from that value. The new code stores the glyph's pitch in bit_pitch, but fails to update the rotated pixel's output accordingly. Simply replacing the variable does this. The bug can be reproduced by setting a font with an unaligned width, such as sun12x22, like this: setfont sun12x22 echo 2 > /sys/class/graphics/fbcon/rotate Without the fix, the font looks distorted. Fixes: a30e9e6b018f ("lib/fonts: Refactor glyph-rotation helpers") Closes: https://lore.gitlab.freedesktop.org/drm-ai-reviews/review-patch7-20260407092555.58816-8-tzimmermann@suse.de/ Cc: dri-devel@lists.freedesktop.org Cc: linux-fbdev@vger.kernel.org Signed-off-by: Thomas Zimmermann Signed-off-by: Helge Deller --- lib/fonts/font_rotate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/fonts/font_rotate.c b/lib/fonts/font_rotate.c index 065e0fc0667b..275406008823 100644 --- a/lib/fonts/font_rotate.c +++ b/lib/fonts/font_rotate.c @@ -106,7 +106,7 @@ static void __font_glyph_rotate_180(const unsigned char *glyph, for (y = 0; y < height; y++) { for (x = 0; x < width; x++) { if (font_glyph_test_bit(glyph, x, y, bit_pitch)) { - font_glyph_set_bit(out, width - (1 + x + shift), height - (1 + y), + font_glyph_set_bit(out, bit_pitch - 1 - x - shift, height - 1 - y, bit_pitch); } }