vt: introduce unicode mode for /dev/vcs

Now that the core vt code knows how to preserve unicode values for each
displayed character, it is then possible to let user space access it via
/dev/vcs*.

Unicode characters are presented as 32 bit values in native endianity
via the /dev/vcsu* devices, mimicking the simple /dev/vcs* devices.
Unicode with attributes (similarly to /dev/vcsa*) is not supported at
the moment.

Data is available only as long as the console is in UTF-8 mode. ENODATA
is returned otherwise.

This was tested with the latest development version (to become
version 5.7) of BRLTTY. Amongst other things, this allows ⠋⠕⠗ ⠞⠓⠊⠎
⠃⠗⠁⠊⠇⠇⠑⠀⠞⠑⠭⠞⠀to appear directly on braille displays regardless of the
console font being used.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Dave Mielke <Dave@mielke.cc>
Acked-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nicolas Pitre 2018-06-26 23:56:41 -04:00 committed by Greg Kroah-Hartman
parent d8ae724271
commit d21b0be246
3 changed files with 141 additions and 14 deletions

View file

@ -42,4 +42,9 @@ extern u16 vcs_scr_readw(struct vc_data *vc, const u16 *org);
extern void vcs_scr_writew(struct vc_data *vc, u16 val, u16 *org);
extern void vcs_scr_updated(struct vc_data *vc);
extern int vc_uniscr_check(struct vc_data *vc);
extern void vc_uniscr_copy_line(struct vc_data *vc, void *dest,
unsigned int row, unsigned int col,
unsigned int nr);
#endif