drm/i915/backlight: Fix backlight takeover on LPT, v3.

[tomoyo/tomoyo-test1.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 bb8612a..beca98d 100644 (file)
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -1496,8 +1496,8 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus
 {
        struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
        struct intel_panel *panel = &connector->panel;
-       u32 pch_ctl1, pch_ctl2, val;
-       bool alt;
+       u32 cpu_ctl2, pch_ctl1, pch_ctl2, val;
+       bool alt, cpu_mode;
 
        if (HAS_PCH_LPT(dev_priv))
                alt = I915_READ(SOUTH_CHICKEN2) & LPT_PWM_GRANULARITY;
@@ -1511,6 +1511,8 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus
        pch_ctl2 = I915_READ(BLC_PWM_PCH_CTL2);
        panel->backlight.max = pch_ctl2 >> 16;
 
+       cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
+
        if (!panel->backlight.max)
                panel->backlight.max = get_backlight_max_vbt(connector);
 
@@ -1519,12 +1521,28 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus
 
        panel->backlight.min = get_backlight_min_vbt(connector);
 
-       val = lpt_get_backlight(connector);
+       panel->backlight.enabled = pch_ctl1 & BLM_PCH_PWM_ENABLE;
+
+       cpu_mode = panel->backlight.enabled && HAS_PCH_LPT(dev_priv) &&
+                  !(pch_ctl1 & BLM_PCH_OVERRIDE_ENABLE) &&
+                  (cpu_ctl2 & BLM_PWM_ENABLE);
+       if (cpu_mode)
+               val = pch_get_backlight(connector);
+       else
+               val = lpt_get_backlight(connector);
        val = intel_panel_compute_brightness(connector, val);
        panel->backlight.level = clamp(val, panel->backlight.min,
                                       panel->backlight.max);
 
-       panel->backlight.enabled = pch_ctl1 & BLM_PCH_PWM_ENABLE;
+       if (cpu_mode) {
+               DRM_DEBUG_KMS("CPU backlight register was enabled, switching to PCH override\n");
+
+               /* Write converted CPU PWM value to PCH override register */
+               lpt_set_backlight(connector->base.state, panel->backlight.level);
+               I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1 | BLM_PCH_OVERRIDE_ENABLE);
+
+               I915_WRITE(BLC_PWM_CPU_CTL2, cpu_ctl2 & ~BLM_PWM_ENABLE);
+       }
 
        return 0;
 }