drm/i915: Revive combination mode for backlight control

[mv-sheeva.git] / drivers / gpu / drm / i915 / intel_panel.c

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index d860abeda70f54905355ceae824174ae0e19943b..f8f86e57df2264c4578f10935b48f78370f49d4c 100644 (file)
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -30,6 +30,8 @@
 
 #include "intel_drv.h"
 
+#define PCI_LBPC 0xf4 /* legacy/combination backlight modes */
+
 void
 intel_fixed_panel_mode(struct drm_display_mode *fixed_mode,
                       struct drm_display_mode *adjusted_mode)
@@ -110,6 +112,19 @@ done:
        dev_priv->pch_pf_size = (width << 16) | height;
 }
 
+static int is_backlight_combination_mode(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+
+       if (INTEL_INFO(dev)->gen >= 4)
+               return I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE;
+
+       if (IS_GEN2(dev))
+               return I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE;
+
+       return 0;
+}
+
 static u32 i915_read_blc_pwm_ctl(struct drm_i915_private *dev_priv)
 {
        u32 val;
@@ -166,6 +181,9 @@ u32 intel_panel_get_max_backlight(struct drm_device *dev)
                        if (INTEL_INFO(dev)->gen < 4)
                                max &= ~1;
                }
+
+               if (is_backlight_combination_mode(dev))
+                       max *= 0xff;
        }
 
        DRM_DEBUG_DRIVER("max backlight PWM = %d\n", max);
@@ -183,6 +201,14 @@ u32 intel_panel_get_backlight(struct drm_device *dev)
                val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
                if (IS_PINEVIEW(dev))
                        val >>= 1;
+
+               if (is_backlight_combination_mode(dev)){
+                       u8 lbpc;
+
+                       val &= ~1;
+                       pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc);
+                       val *= lbpc;
+               }
        }
 
        DRM_DEBUG_DRIVER("get backlight PWM = %d\n", val);
@@ -205,6 +231,16 @@ void intel_panel_set_backlight(struct drm_device *dev, u32 level)
 
        if (HAS_PCH_SPLIT(dev))
                return intel_pch_panel_set_backlight(dev, level);
+
+       if (is_backlight_combination_mode(dev)){
+               u32 max = intel_panel_get_max_backlight(dev);
+               u8 lbpc;
+
+               lbpc = level * 0xfe / max + 1;
+               level /= lbpc;
+               pci_write_config_byte(dev->pdev, PCI_LBPC, lbpc);
+       }
+
        tmp = I915_READ(BLC_PWM_CTL);
        if (IS_PINEVIEW(dev)) {
                tmp &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1);