rc: add a backlight service to save/restore backlight levelsHEADmain

The default on my laptop is annoyingly bright, and this is a useful
feature to mitigate that.  The backlight script is largely a copy of the
mixer service which provides the same value for mixers, but this one is
specifically dependant on kld to allow DRM drivers a chance to attach.

Note that it's off by default to avoid interference with DEs, and
document the capability in backlight(8).  Set backlight_enable=YES in
rc.conf(5) to enable save/restore.

Relnotes:	maybe
Reviewed by:	bapt, ivy, manu, ziaee
Differential Revision:	https://reviews.freebsd.org/D59296

0 files changed, 0 insertions, 0 deletions