[kbd] Bug#528357: /usr/bin/showconsolefont: produces garbage

[Michael Schutte]

Hi Alexey,

Somewhere between 2.6.26 and 2.6.29, a change in the Linux kernel has
caused showconsolefont to print garbage instead of spaces.  A Debian
user has provided these two screenshots in his bug report [1]:

    http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=15;filename=showconsolefont-lenny.png;att=1;bug=528357	
    http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=showconsolefont-garbage.png;att=1;bug=528357

[1] http://bugs.debian.org/528357

This happens only when the console is in Unicode mode, which makes it
quite clear that the space character becomes something different in each
unimap showconsolefont switches to.  And indeed, if "\xef\x80\xa0"
(which is the UTF-8 representation of U+F020, a straight-to-font space)
is used instead of " ", everything is fine again for Unicode consoles;
but, not surprisingly, this produces rubbish in XLATE mode.

One way to solve this would be to check which mode the VT is in and then
using the appropriate way to print spaces.  Another idea is forcibly
switching the console to Unicode mode, dumping the font using UTF-8
characters, and then reverting the mode change if necessary, but that
would involve a near-complete rewrite of showconsolefont.c.  There might
be better solutions, but I don’t even know which commit from
linux-2.6.git introduces these problems.

Perhaps I’m also missing something obvious.  Any comments?

All the best,
-- 
Michael Schutte <michi at uiae.at>
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