1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 58f4b02151f2..33aaad30c0bc 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9530,6 +9530,19 @@ static void i915_disable_vga(struct drm_device *dev)
         POSTING_READ(vga_reg);
 }
 
+static void ivb_pch_pwm_override(struct drm_device *dev)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+
+        /*
+         * IVB has CPU eDP backlight regs too, set things up to let the
+         * PCH regs control the backlight
+         */
+        I915_WRITE(BLC_PWM_CPU_CTL2, PWM_ENABLE);
+        I915_WRITE(BLC_PWM_CPU_CTL, 0);
+        I915_WRITE(BLC_PWM_PCH_CTL1, PWM_ENABLE | (1<<30));
+}
+
 void intel_modeset_init_hw(struct drm_device *dev)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
@@ -9545,6 +9558,9 @@ void intel_modeset_init_hw(struct drm_device *dev)
                 gen6_enable_rps(dev_priv);
                 gen6_update_ring_freq(dev_priv);
         }
+
+        if (IS_IVYBRIDGE(dev))
+                ivb_pch_pwm_override(dev);
 }
 
 void intel_modeset_init(struct drm_device *dev)