console ASCII glyph 1:1 mapping

For the console, there is a 1:1 mapping of glyphs which cannot be found
in the current font. This seems to be meant as a kind of 'emergency
fallback' for fonts without unicode mapping which otherwise would
display nothing readable on the screen.

At the moment it affects all chars for which no substitution character
is defined. In particular this means that for all chars (>= 128) where
there is no iso88591-1/unicode character (e.g. control character area)
you'll get the very strange 1:1 mapping of the (cp437) graphics card
glyphs.

I'm pretty sure that the 1:1 mapping should only affect strict ASCII
code characters, i.e. chars < 128.

The patch limits the mapping as it probably was meant anyway.

Signed-off-by: Ingo Brueckl <ib@wupperonline.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Egmont Koblinger <egmont@uhulinux.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

authored by

Ingo Brueckl and committed by
Linus Torvalds
1c55f187 f75bc06e

+1 -1
+1 -1
drivers/char/vt.c
··· 2274 2274 continue; /* nothing to display */ 2275 2275 } 2276 2276 /* Glyph not found */ 2277 - if ((!(vc->vc_utf && !vc->vc_disp_ctrl) || c < 128) && !(c & ~charmask)) { 2277 + if ((!(vc->vc_utf && !vc->vc_disp_ctrl) && c < 128) && !(c & ~charmask)) { 2278 2278 /* In legacy mode use the glyph we get by a 1:1 mapping. 2279 2279 This would make absolutely no sense with Unicode in mind, 2280 2280 but do this for ASCII characters since a font may lack