[Intel-gfx] [PATCH] drm/i915: Correctly read backlight PWM for pipe B on vlv/chv

[rafael.barbalho at intel.com]

From: Rafael Barbalho <rafael.barbalho at intel.com>

Make the vlv/chv backlight setup more generic by actually looking at which
pipe the panel is attached to and read the backlight PWM registers that were
setup by the bios from that pipe.

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Rafael Barbalho <rafael.barbalho at intel.com>
---
 drivers/gpu/drm/i915/intel_panel.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 59b028f..be75d76 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -1200,32 +1200,28 @@ static int vlv_setup_backlight(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;
-	enum pipe pipe;
+	enum pipe pipe = intel_get_pipe_from_connector(connector);
 	u32 ctl, ctl2, val;
 
-	for_each_pipe(pipe) {
-		u32 cur_val = I915_READ(VLV_BLC_PWM_CTL(pipe));
+	ctl2 = I915_READ(VLV_BLC_PWM_CTL2(pipe));
+	panel->backlight.active_low_pwm = ctl2 & BLM_POLARITY_I965;
 
-		/* Skip if the modulation freq is already set */
-		if (cur_val & ~BACKLIGHT_DUTY_CYCLE_MASK)
-			continue;
+	ctl = I915_READ(VLV_BLC_PWM_CTL(pipe));
 
-		cur_val &= BACKLIGHT_DUTY_CYCLE_MASK;
-		I915_WRITE(VLV_BLC_PWM_CTL(pipe), (0xf42 << 16) |
-			   cur_val);
+	/* Skip if the modulation freq is already set */
+	if ((ctl & ~BACKLIGHT_DUTY_CYCLE_MASK) == 0) {
+		ctl &= BACKLIGHT_DUTY_CYCLE_MASK;
+		ctl |= (0xf42 << 16);
+		I915_WRITE(VLV_BLC_PWM_CTL(pipe), ctl);
 	}
 
-	ctl2 = I915_READ(VLV_BLC_PWM_CTL2(PIPE_A));
-	panel->backlight.active_low_pwm = ctl2 & BLM_POLARITY_I965;
-
-	ctl = I915_READ(VLV_BLC_PWM_CTL(PIPE_A));
 	panel->backlight.max = ctl >> 16;
 	if (!panel->backlight.max)
 		return -ENODEV;
 
 	panel->backlight.min = get_backlight_min_vbt(connector);
 
-	val = _vlv_get_backlight(dev, PIPE_A);
+	val = _vlv_get_backlight(dev, pipe);
 	panel->backlight.level = intel_panel_compute_brightness(connector, val);
 
 	panel->backlight.enabled = (ctl2 & BLM_PWM_ENABLE) &&
-- 
2.0.3