Comment 1 for bug 1625932

The upstream bug
https://bugs.freedesktop.org/show_bug.cgi?id=97486

And the issue could be fixed by the following 2 commits in drm-intel-next-queued.

commit 32b421e79e6b546da1d469f1229403ac9142d695
Author: Jani Nikula <email address hidden>
Date: Mon Sep 19 13:35:25 2016 +0300

    drm/i915/backlight: setup and cache pwm alternate increment value

and

commit e29aff05f239f8dd24e9ee7816fd96726e20105a
Author: Shawn Lee <email address hidden>
Date: Mon Sep 19 13:35:26 2016 +0300

    drm/i915/backlight: setup backlight pwm alternate increment on backlight enable