1 files changed, 187 insertions, 22 deletions

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 12b02fe1d0a..41b3be21749 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -398,6 +398,68 @@ intel_panel_detect(struct drm_device *dev)
 	}
 }
 
+/**
+ * scale - scale values from one range to another
+ *
+ * @source_val: value in range [@source_min..@source_max]
+ *
+ * Return @source_val in range [@source_min..@source_max] scaled to range
+ * [@target_min..@target_max].
+ */
+static uint32_t scale(uint32_t source_val,
+		      uint32_t source_min, uint32_t source_max,
+		      uint32_t target_min, uint32_t target_max)
+{
+	uint64_t target_val;
+
+	WARN_ON(source_min > source_max);
+	WARN_ON(target_min > target_max);
+
+	/* defensive */
+	source_val = clamp(source_val, source_min, source_max);
+
+	/* avoid overflows */
+	target_val = DIV_ROUND_CLOSEST_ULL((uint64_t)(source_val - source_min) *
+			(target_max - target_min), source_max - source_min);
+	target_val += target_min;
+
+	return target_val;
+}
+
+/* Scale user_level in range [0..user_max] to [hw_min..hw_max]. */
+static inline u32 scale_user_to_hw(struct intel_connector *connector,
+				   u32 user_level, u32 user_max)
+{
+	struct intel_panel *panel = &connector->panel;
+
+	return scale(user_level, 0, user_max,
+		     panel->backlight.min, panel->backlight.max);
+}
+
+/* Scale user_level in range [0..user_max] to [0..hw_max], clamping the result
+ * to [hw_min..hw_max]. */
+static inline u32 clamp_user_to_hw(struct intel_connector *connector,
+				   u32 user_level, u32 user_max)
+{
+	struct intel_panel *panel = &connector->panel;
+	u32 hw_level;
+
+	hw_level = scale(user_level, 0, user_max, 0, panel->backlight.max);
+	hw_level = clamp(hw_level, panel->backlight.min, panel->backlight.max);
+
+	return hw_level;
+}
+
+/* Scale hw_level in range [hw_min..hw_max] to [0..user_max]. */
+static inline u32 scale_hw_to_user(struct intel_connector *connector,
+				   u32 hw_level, u32 user_max)
+{
+	struct intel_panel *panel = &connector->panel;
+
+	return scale(hw_level, panel->backlight.min, panel->backlight.max,
+		     0, user_max);
+}
+
 static u32 intel_panel_compute_brightness(struct intel_connector *connector,
 					  u32 val)
 {
@@ -557,17 +619,16 @@ intel_panel_actually_set_backlight(struct intel_connector *connector, u32 level)
 	dev_priv->display.set_backlight(connector, level);
 }
 
-/* set backlight brightness to level in range [0..max] */
-void intel_panel_set_backlight(struct intel_connector *connector, u32 level,
-			       u32 max)
+/* set backlight brightness to level in range [0..max], scaling wrt hw min */
+static void intel_panel_set_backlight(struct intel_connector *connector,
+				      u32 user_level, u32 user_max)
 {
 	struct drm_device *dev = connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_panel *panel = &connector->panel;
 	enum pipe pipe = intel_get_pipe_from_connector(connector);
-	u32 freq;
+	u32 hw_level;
 	unsigned long flags;
-	u64 n;
 
 	if (!panel->backlight.present || pipe == INVALID_PIPE)
 		return;
@@ -576,18 +637,46 @@ void intel_panel_set_backlight(struct intel_connector *connector, u32 level,
 
 	WARN_ON(panel->backlight.max == 0);
 
-	/* scale to hardware max, but be careful to not overflow */
-	freq = panel->backlight.max;
-	n = (u64)level * freq;
-	do_div(n, max);
-	level = n;
+	hw_level = scale_user_to_hw(connector, user_level, user_max);
+	panel->backlight.level = hw_level;
+
+	if (panel->backlight.enabled)
+		intel_panel_actually_set_backlight(connector, hw_level);
+
+	spin_unlock_irqrestore(&dev_priv->backlight_lock, flags);
+}
+
+/* set backlight brightness to level in range [0..max], assuming hw min is
+ * respected.
+ */
+void intel_panel_set_backlight_acpi(struct intel_connector *connector,
+				    u32 user_level, u32 user_max)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_panel *panel = &connector->panel;
+	enum pipe pipe = intel_get_pipe_from_connector(connector);
+	u32 hw_level;
+	unsigned long flags;
+
+	if (!panel->backlight.present || pipe == INVALID_PIPE)
+		return;
+
+	spin_lock_irqsave(&dev_priv->backlight_lock, flags);
+
+	WARN_ON(panel->backlight.max == 0);
+
+	hw_level = clamp_user_to_hw(connector, user_level, user_max);
+	panel->backlight.level = hw_level;
 
-	panel->backlight.level = level;
 	if (panel->backlight.device)
-		panel->backlight.device->props.brightness = level;
+		panel->backlight.device->props.brightness =
+			scale_hw_to_user(connector,
+					 panel->backlight.level,
+					 panel->backlight.device->props.max_brightness);
 
 	if (panel->backlight.enabled)
-		intel_panel_actually_set_backlight(connector, level);
+		intel_panel_actually_set_backlight(connector, hw_level);
 
 	spin_unlock_irqrestore(&dev_priv->backlight_lock, flags);
 }
@@ -661,6 +750,8 @@ void intel_panel_disable_backlight(struct intel_connector *connector)
 
 	spin_lock_irqsave(&dev_priv->backlight_lock, flags);
 
+	if (panel->backlight.device)
+		panel->backlight.device->props.power = FB_BLANK_POWERDOWN;
 	panel->backlight.enabled = false;
 	dev_priv->display.disable_backlight(connector);
 
@@ -711,7 +802,7 @@ static void pch_enable_backlight(struct intel_connector *connector)
 
 	cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
 	if (cpu_ctl2 & BLM_PWM_ENABLE) {
-		WARN(1, "cpu backlight already enabled\n");
+		DRM_DEBUG_KMS("cpu backlight already enabled\n");
 		cpu_ctl2 &= ~BLM_PWM_ENABLE;
 		I915_WRITE(BLC_PWM_CPU_CTL2, cpu_ctl2);
 	}
@@ -755,7 +846,7 @@ static void i9xx_enable_backlight(struct intel_connector *connector)
 
 	ctl = I915_READ(BLC_PWM_CTL);
 	if (ctl & BACKLIGHT_DUTY_CYCLE_MASK_PNV) {
-		WARN(1, "backlight already enabled\n");
+		DRM_DEBUG_KMS("backlight already enabled\n");
 		I915_WRITE(BLC_PWM_CTL, 0);
 	}
 
@@ -786,7 +877,7 @@ static void i965_enable_backlight(struct intel_connector *connector)
 
 	ctl2 = I915_READ(BLC_PWM_CTL2);
 	if (ctl2 & BLM_PWM_ENABLE) {
-		WARN(1, "backlight already enabled\n");
+		DRM_DEBUG_KMS("backlight already enabled\n");
 		ctl2 &= ~BLM_PWM_ENABLE;
 		I915_WRITE(BLC_PWM_CTL2, ctl2);
 	}
@@ -820,7 +911,7 @@ static void vlv_enable_backlight(struct intel_connector *connector)
 
 	ctl2 = I915_READ(VLV_BLC_PWM_CTL2(pipe));
 	if (ctl2 & BLM_PWM_ENABLE) {
-		WARN(1, "backlight already enabled\n");
+		DRM_DEBUG_KMS("backlight already enabled\n");
 		ctl2 &= ~BLM_PWM_ENABLE;
 		I915_WRITE(VLV_BLC_PWM_CTL2(pipe), ctl2);
 	}
@@ -860,11 +951,15 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
 		panel->backlight.level = panel->backlight.max;
 		if (panel->backlight.device)
 			panel->backlight.device->props.brightness =
-				panel->backlight.level;
+				scale_hw_to_user(connector,
+						 panel->backlight.level,
+						 panel->backlight.device->props.max_brightness);
 	}
 
 	dev_priv->display.enable_backlight(connector);
 	panel->backlight.enabled = true;
+	if (panel->backlight.device)
+		panel->backlight.device->props.power = FB_BLANK_UNBLANK;
 
 	spin_unlock_irqrestore(&dev_priv->backlight_lock, flags);
 }
@@ -873,6 +968,7 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
 static int intel_backlight_device_update_status(struct backlight_device *bd)
 {
 	struct intel_connector *connector = bl_get_data(bd);
+	struct intel_panel *panel = &connector->panel;
 	struct drm_device *dev = connector->base.dev;
 
 	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
@@ -880,6 +976,23 @@ static int intel_backlight_device_update_status(struct backlight_device *bd)
 		      bd->props.brightness, bd->props.max_brightness);
 	intel_panel_set_backlight(connector, bd->props.brightness,
 				  bd->props.max_brightness);
+
+	/*
+	 * Allow flipping bl_power as a sub-state of enabled. Sadly the
+	 * backlight class device does not make it easy to to differentiate
+	 * between callbacks for brightness and bl_power, so our backlight_power
+	 * callback needs to take this into account.
+	 */
+	if (panel->backlight.enabled) {
+		if (panel->backlight_power) {
+			bool enable = bd->props.power == FB_BLANK_UNBLANK &&
+				bd->props.brightness != 0;
+			panel->backlight_power(connector, enable);
+		}
+	} else {
+		bd->props.power = FB_BLANK_POWERDOWN;
+	}
+
 	drm_modeset_unlock(&dev->mode_config.connection_mutex);
 	return 0;
 }
@@ -889,11 +1002,15 @@ static int intel_backlight_device_get_brightness(struct backlight_device *bd)
 	struct intel_connector *connector = bl_get_data(bd);
 	struct drm_device *dev = connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 hw_level;
 	int ret;
 
 	intel_runtime_pm_get(dev_priv);
 	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
-	ret = intel_panel_get_backlight(connector);
+
+	hw_level = intel_panel_get_backlight(connector);
+	ret = scale_hw_to_user(connector, hw_level, bd->props.max_brightness);
+
 	drm_modeset_unlock(&dev->mode_config.connection_mutex);
 	intel_runtime_pm_put(dev_priv);
 
@@ -913,12 +1030,24 @@ static int intel_backlight_device_register(struct intel_connector *connector)
 	if (WARN_ON(panel->backlight.device))
 		return -ENODEV;
 
-	BUG_ON(panel->backlight.max == 0);
+	WARN_ON(panel->backlight.max == 0);
 
 	memset(&props, 0, sizeof(props));
 	props.type = BACKLIGHT_RAW;
-	props.brightness = panel->backlight.level;
+
+	/*
+	 * Note: Everything should work even if the backlight device max
+	 * presented to the userspace is arbitrarily chosen.
+	 */
 	props.max_brightness = panel->backlight.max;
+	props.brightness = scale_hw_to_user(connector,
+					    panel->backlight.level,
+					    props.max_brightness);
+
+	if (panel->backlight.enabled)
+		props.power = FB_BLANK_UNBLANK;
+	else
+		props.power = FB_BLANK_POWERDOWN;
 
 	/*
 	 * Note: using the same name independent of the connector prevents
@@ -964,6 +1093,32 @@ static void intel_backlight_device_unregister(struct intel_connector *connector)
  * XXX: Query mode clock or hardware clock and program PWM modulation frequency
  * appropriately when it's 0. Use VBT and/or sane defaults.
  */
+static u32 get_backlight_min_vbt(struct intel_connector *connector)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_panel *panel = &connector->panel;
+	int min;
+
+	WARN_ON(panel->backlight.max == 0);
+
+	/*
+	 * XXX: If the vbt value is 255, it makes min equal to max, which leads
+	 * to problems. There are such machines out there. Either our
+	 * interpretation is wrong or the vbt has bogus data. Or both. Safeguard
+	 * against this by letting the minimum be at most (arbitrarily chosen)
+	 * 25% of the max.
+	 */
+	min = clamp_t(int, dev_priv->vbt.backlight.min_brightness, 0, 64);
+	if (min != dev_priv->vbt.backlight.min_brightness) {
+		DRM_DEBUG_KMS("clamping VBT min backlight %d/255 to %d/255\n",
+			      dev_priv->vbt.backlight.min_brightness, min);
+	}
+
+	/* vbt value is a coefficient in range [0..255] */
+	return scale(min, 0, 255, 0, panel->backlight.max);
+}
+
 static int bdw_setup_backlight(struct intel_connector *connector)
 {
 	struct drm_device *dev = connector->base.dev;
@@ -979,6 +1134,8 @@ static int bdw_setup_backlight(struct intel_connector *connector)
 	if (!panel->backlight.max)
 		return -ENODEV;
 
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
 	val = bdw_get_backlight(connector);
 	panel->backlight.level = intel_panel_compute_brightness(connector, val);
 
@@ -1003,6 +1160,8 @@ static int pch_setup_backlight(struct intel_connector *connector)
 	if (!panel->backlight.max)
 		return -ENODEV;
 
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
 	val = pch_get_backlight(connector);
 	panel->backlight.level = intel_panel_compute_brightness(connector, val);
 
@@ -1035,6 +1194,8 @@ static int i9xx_setup_backlight(struct intel_connector *connector)
 	if (!panel->backlight.max)
 		return -ENODEV;
 
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
 	val = i9xx_get_backlight(connector);
 	panel->backlight.level = intel_panel_compute_brightness(connector, val);
 
@@ -1062,6 +1223,8 @@ static int i965_setup_backlight(struct intel_connector *connector)
 	if (!panel->backlight.max)
 		return -ENODEV;
 
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
 	val = i9xx_get_backlight(connector);
 	panel->backlight.level = intel_panel_compute_brightness(connector, val);
 
@@ -1079,7 +1242,7 @@ static int vlv_setup_backlight(struct intel_connector *connector)
 	enum pipe pipe;
 	u32 ctl, ctl2, val;
 
-	for_each_pipe(pipe) {
+	for_each_pipe(dev_priv, pipe) {
 		u32 cur_val = I915_READ(VLV_BLC_PWM_CTL(pipe));
 
 		/* Skip if the modulation freq is already set */
@@ -1099,6 +1262,8 @@ static int vlv_setup_backlight(struct intel_connector *connector)
 	if (!panel->backlight.max)
 		return -ENODEV;
 
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
 	val = _vlv_get_backlight(dev, PIPE_A);
 	panel->backlight.level = intel_panel_compute_brightness(connector, val);