drm/i915: Refactor panel backlight controls

There were two instances of code to control the panel backlight and
neither handled the complete set of device variations.

Fixes:

  Bug 29716 - [GM965] Regression: Backlight resets to minimum when changing resolution
  https://bugs.freedesktop.org/show_bug.cgi?id=29716

And a bug on one of my PineView boxes which overflowed the backlight
value.

Incorporates part of a similar patch by Matthew Garrett that exposes a
native Intel backlight controller.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e6fbeb43d59c..cfc8bfd0fd7e 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -319,7 +319,7 @@ typedef struct drm_i915_private {
         struct intel_overlay *overlay;
 
         /* LVDS info */
-        int backlight_duty_cycle;  /* restore backlight to this value */
+        int backlight_level;  /* restore backlight to this value */
         bool panel_wants_dither;
         struct drm_display_mode *panel_fixed_mode;
         struct drm_display_mode *lfp_lvds_vbt_mode; /* if any */