drm/i915: make backlight functions take a connector

On VLV/BYT, backlight controls a per-pipe, so when adjusting the
backlight we need to pass the correct info.  So make the externally
visible backlight functions take a connector argument, which can be used
internally to figure out the pipe backlight to adjust.

v2: make connector pipe lookup check for NULL crtc (Jani)
    fixup connector check in ASLE code (Jani)
v3: make sure we take the mode config lock around lookups (Daniel)
v4: fix double unlock in panel_get_brightness (Daniel)
v5: push ASLE work into a work queue (Daniel)
v6: separate ASLE work to a prep patch, rebase (Jani)

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index d58fbb6..4609eed 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1249,7 +1249,6 @@
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
 	struct drm_device *dev = intel_dig_port->base.base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	int pipe = to_intel_crtc(intel_dig_port->base.base.crtc)->pipe;
 	u32 pp;
 	u32 pp_ctrl_reg;
 
@@ -1272,7 +1271,7 @@
 	I915_WRITE(pp_ctrl_reg, pp);
 	POSTING_READ(pp_ctrl_reg);
 
-	intel_panel_enable_backlight(dev, pipe);
+	intel_panel_enable_backlight(intel_dp->attached_connector);
 }
 
 void ironlake_edp_backlight_off(struct intel_dp *intel_dp)
@@ -1285,7 +1284,7 @@
 	if (!is_edp(intel_dp))
 		return;
 
-	intel_panel_disable_backlight(dev);
+	intel_panel_disable_backlight(intel_dp->attached_connector);
 
 	DRM_DEBUG_KMS("\n");
 	pp = ironlake_get_pp_control(intel_dp);