drm/i915: backlight sysfs bl_power and brightness == 0

This series adds support for backlight class sysfs bl_power attribute for eDP panels, which allows switching the backlight on/off. This is done using the eDP panel power control as a sub-state of everything else being enabled. Patch 4 also makes 0 brightness switch off the eDP backlight using the same mechanism. This is all eDP specific, with no support for LVDS.

I'm not particularly fond of these patches, but there appears to be demand for them, particularly since

commit 6dda730e55f412a6dfb181cae6784822ba463847

Author: Jani Nikula <[email protected]>
Date:   Tue Jun 24 18:27:40 2014 +0300

drm/i915: respect the VBT minimum backlight brightness

All the discussions seem to just drag on and on without code to speak about, so here goes. I've tried to make this as simple and unintrusive as possible.

BR,
Jani.

Jani Nikula (4):
drm/i915/dp: split up panel power control from backlight pwm control drm/i915: add some framework for backlight bl_power support drm/i915/dp: make backlight bl_power control power sequencer backlight drm/i915: switch off backlight for backlight class 0 brightness

 drivers/gpu/drm/i915/intel_dp.c    | 61 ++++++++++++++++++++++++++++++--------
 drivers/gpu/drm/i915/intel_drv.h   |  2 ++
 drivers/gpu/drm/i915/intel_panel.c | 27 +++++++++++++++++
 3 files changed, 77 insertions(+), 13 deletions(-)

1.9.1