linux: Use K_OFF VT KB mode over K_RAW if available.

Linux kernels since 2.6.38 (March 2011) have an VT KB mode K_OFF in
which special keys (like Ctrl+C) are not interpreted and input is not
buffered. Use of this mode over K_RAW removes the need for a
xf86ConsoleHandler to drain the VT input buffer, removing the grief it
causes when it goes wrong or is (de)initialized out-of-order. (This
also saves a few needless context switches per key event.)

If K_OFF is not defined or not understood by the kernel, K_RAW and the
previous method is used as a fall-back.

Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Arthur Taylor <art@ified.ca>
Signed-off-by: Keith Packard <keithp@keithp.com>

0 files changed, 0 insertions, 0 deletions