drm/i915/backlight: handle enabled but zero duty cycle at module load

Don't consider enabled but zero duty cycle backlight disabled. Clamp
level between min and max for sanity.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1471939811-9817-1-git-send-email-maarten.lankhorst@linux.intel.com
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 96c65d77e8866b0c25beadb46e342ecc8e37e9d6..c10e9b0405e8035d96d990286a65ed37bc550a39 100644 (file)
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -1430,10 +1430,11 @@ 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.level = intel_panel_compute_brightness(connector, val);
+       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) &&
-               panel->backlight.level != 0;
+       panel->backlight.enabled = pch_ctl1 & BLM_PCH_PWM_ENABLE;
 
        return 0;
 }
@@ -1459,11 +1460,13 @@ static int pch_setup_backlight(struct intel_connector *connector, enum pipe unus
        panel->backlight.min = get_backlight_min_vbt(connector);
 
        val = pch_get_backlight(connector);
-       panel->backlight.level = intel_panel_compute_brightness(connector, val);
+       val = intel_panel_compute_brightness(connector, val);
+       panel->backlight.level = clamp(val, panel->backlight.min,
+                                      panel->backlight.max);
 
        cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
        panel->backlight.enabled = (cpu_ctl2 & BLM_PWM_ENABLE) &&
-               (pch_ctl1 & BLM_PCH_PWM_ENABLE) && panel->backlight.level != 0;
+               (pch_ctl1 & BLM_PCH_PWM_ENABLE);
 
        return 0;
 }
@@ -1498,9 +1501,11 @@ static int i9xx_setup_backlight(struct intel_connector *connector, enum pipe unu
        panel->backlight.min = get_backlight_min_vbt(connector);
 
        val = i9xx_get_backlight(connector);
-       panel->backlight.level = intel_panel_compute_brightness(connector, val);
+       val = intel_panel_compute_brightness(connector, val);
+       panel->backlight.level = clamp(val, panel->backlight.min,
+                                      panel->backlight.max);
 
-       panel->backlight.enabled = panel->backlight.level != 0;
+       panel->backlight.enabled = val != 0;
 
        return 0;
 }
@@ -1530,10 +1535,11 @@ static int i965_setup_backlight(struct intel_connector *connector, enum pipe unu
        panel->backlight.min = get_backlight_min_vbt(connector);
 
        val = i9xx_get_backlight(connector);
-       panel->backlight.level = intel_panel_compute_brightness(connector, val);
+       val = intel_panel_compute_brightness(connector, val);
+       panel->backlight.level = clamp(val, panel->backlight.min,
+                                      panel->backlight.max);
 
-       panel->backlight.enabled = (ctl2 & BLM_PWM_ENABLE) &&
-               panel->backlight.level != 0;
+       panel->backlight.enabled = ctl2 & BLM_PWM_ENABLE;
 
        return 0;
 }
@@ -1562,10 +1568,11 @@ static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe
        panel->backlight.min = get_backlight_min_vbt(connector);
 
        val = _vlv_get_backlight(dev_priv, pipe);
-       panel->backlight.level = intel_panel_compute_brightness(connector, val);
+       val = intel_panel_compute_brightness(connector, val);
+       panel->backlight.level = clamp(val, panel->backlight.min,
+                                      panel->backlight.max);
 
-       panel->backlight.enabled = (ctl2 & BLM_PWM_ENABLE) &&
-               panel->backlight.level != 0;
+       panel->backlight.enabled = ctl2 & BLM_PWM_ENABLE;
 
        return 0;
 }
@@ -1607,10 +1614,11 @@ bxt_setup_backlight(struct intel_connector *connector, enum pipe unused)
                return -ENODEV;
 
        val = bxt_get_backlight(connector);
-       panel->backlight.level = intel_panel_compute_brightness(connector, val);
+       val = intel_panel_compute_brightness(connector, val);
+       panel->backlight.level = clamp(val, panel->backlight.min,
+                                      panel->backlight.max);
 
-       panel->backlight.enabled = (pwm_ctl & BXT_BLC_PWM_ENABLE) &&
-               panel->backlight.level != 0;
+       panel->backlight.enabled = pwm_ctl & BXT_BLC_PWM_ENABLE;
 
        return 0;
 }