From 6802f3591fdc732d2460eed3112b02cc07acab8f Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Wed, 7 May 2025 10:13:22 -0400 Subject: [PATCH] vt: make use of ucs_get_fallback() when glyph is unavailable MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Attempt to display a fallback character when given character doesn't have an available glyph. The substitution may not be as good as the original character but still way more helpful than a squared question mark. Example substitutions: À -> A, ç -> c, ø -> o, ─ -> -, © -> C, etc. See gen_ucs_fallback_table.py for a comprehensive list. Signed-off-by: Nicolas Pitre Link: https://lore.kernel.org/r/20250507141535.40655-8-nico@fluxnic.net Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index 556af82a9231..efb761454166 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -3007,6 +3007,19 @@ static int vc_get_glyph(struct vc_data *vc, int tc) return tc; } + /* + * The Unicode screen memory is allocated only when required. + * This is one such case: we're about to "cheat" with the displayed + * character meaning the simple screen buffer won't hold the original + * information, whereas the Unicode screen buffer always does. + */ + vc_uniscr_check(vc); + + /* Try getting a simpler fallback character. */ + tc = ucs_get_fallback(tc); + if (tc) + return vc_get_glyph(vc, tc); + /* Display U+FFFD (Unicode Replacement Character). */ return conv_uni_to_pc(vc, UCS_REPLACEMENT); } -- 2.51.0