[Intel-gfx] [PATCH 5/5] drm/i915/bxt: Use correct live status register for BXT platform

[Jani Nikula]

BXT platform uses live status bits from 0x44440 register to obtain DP
status on hotplug. The existing g4x_digital_port_connected() uses a
different register and hence misses DP hotplug events on BXT
platform. This patch fixes it by using the appropriate register(0x44440)
and live status bits(3:5).

Based on a patch by Durgadoss R <durgadoss.r at intel.com>, from whom the
commit message is shamelessly copy pasted.

Reported-by: Durgadoss R <durgadoss.r at intel.com>
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index bc3b94fa15cb..c6d4bb62e83a 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4561,6 +4561,28 @@ static int vlv_digital_port_connected(struct drm_i915_private *dev_priv,
 	return I915_READ(PORT_HOTPLUG_STAT) & bit ? 1 : 0;
 }
 
+static int bxt_digital_port_connected(struct drm_i915_private *dev_priv,
+				      struct intel_digital_port *port)
+{
+	u32 bit;
+
+	switch (port->port) {
+	case PORT_A:
+		bit = BXT_DE_PORT_HP_DDIA;
+		break;
+	case PORT_B:
+		bit = BXT_DE_PORT_HP_DDIB;
+		break;
+	case PORT_C:
+		bit = BXT_DE_PORT_HP_DDIC;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return I915_READ(GEN8_DE_PORT_ISR) & bit ? 1 : 0;
+}
+
 /*
  * intel_digital_port_connected - is the specified port connected?
  * @dev_priv: i915 private structure
@@ -4577,6 +4599,8 @@ static int intel_digital_port_connected(struct drm_i915_private *dev_priv,
 		return cpt_digital_port_connected(dev_priv, port);
 	else if (IS_VALLEYVIEW(dev_priv))
 		return vlv_digital_port_connected(dev_priv, port);
+	else if (IS_BROXTON(dev_priv))
+		return bxt_digital_port_connected(dev_priv, port);
 	else
 		return g4x_digital_port_connected(dev_priv, port);
 }
-- 
2.1.4