[Intel-gfx] [PATCH] drm/i915/skl: Select DDIA lane capability based upon vbt

[Sonika Jindal]

Currently, if bios fails to drive an edp panel due to any reason,
the ddi buffer will not be enabled. And the DDIA lane capability
will remain 0. This leads to assumption of DDIA x2 which means DDIA
supports 2 lanes and DDIE supports 2 lanes. For some higher resolution
panel which needs 4 lanes, we end up using only 2 lanes which doesn't
let the modeset go through because of limited data rate avalaible.

So, set the DDIA lane capability correctly if port E is being used
by any child device or not.

Cc: Sivakumar Thulasimani <sivakumar.thulasimani at intel.com>
Signed-off-by: Sonika Jindal <sonika.jindal at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h   |    1 +
 drivers/gpu/drm/i915/intel_bios.c |    4 ++++
 drivers/gpu/drm/i915/intel_bios.h |    1 +
 drivers/gpu/drm/i915/intel_ddi.c  |    8 ++++++++
 4 files changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 79da7f3..9aad54b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1384,6 +1384,7 @@ struct intel_vbt_data {
 	union child_device_config *child_dev;
 
 	struct ddi_vbt_port_info ddi_port_info[I915_MAX_PORTS];
+	unsigned int ddi_e_used;
 };
 
 enum intel_ddb_partitioning {
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index c08368c..16c5885 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1119,6 +1119,9 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
 			dev_priv->vbt.dsi.port = p_child->common.dvo_port;
 		}
 
+		if (p_child->common.dvo_port == DVO_PORT_DPE)
+			dev_priv->vbt.ddi_e_used = 1;
+
 		child_dev_ptr = dev_priv->vbt.child_dev + count;
 		count++;
 		memcpy((void *)child_dev_ptr, (void *)p_child,
@@ -1169,6 +1172,7 @@ init_vbt_defaults(struct drm_i915_private *dev_priv)
 		info->supports_hdmi = info->supports_dvi;
 		info->supports_dp = (port != PORT_E);
 	}
+	dev_priv->vbt.ddi_e_used = 0;
 }
 
 static int intel_no_opregion_vbt_callback(const struct dmi_system_id *id)
diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
index af0b476..dd85812 100644
--- a/drivers/gpu/drm/i915/intel_bios.h
+++ b/drivers/gpu/drm/i915/intel_bios.h
@@ -764,6 +764,7 @@ int intel_parse_bios(struct drm_device *dev);
 #define DVO_PORT_DPC	8
 #define DVO_PORT_DPD	9
 #define DVO_PORT_DPA	10
+#define DVO_PORT_DPE	11
 #define DVO_PORT_MIPIA	21
 #define DVO_PORT_MIPIB	22
 #define DVO_PORT_MIPIC	23
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index b974f8e..c8e370a 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2139,6 +2139,7 @@ void intel_ddi_init(struct drm_device *dev, enum port port)
 	struct intel_encoder *intel_encoder;
 	struct drm_encoder *encoder;
 	bool init_hdmi, init_dp;
+	int val;
 
 	init_hdmi = (dev_priv->vbt.ddi_port_info[port].supports_dvi ||
 		     dev_priv->vbt.ddi_port_info[port].supports_hdmi);
@@ -2169,6 +2170,13 @@ void intel_ddi_init(struct drm_device *dev, enum port port)
 	intel_encoder->get_config = intel_ddi_get_config;
 
 	intel_dig_port->port = port;
+
+	val = I915_READ(DDI_BUF_CTL(port));
+	if (IS_SKYLAKE(dev) && port == PORT_A
+		&& !(val & DDI_BUF_CTL_ENABLE)
+		&& !dev_priv->vbt.ddi_e_used)
+		I915_WRITE(DDI_BUF_CTL(port), val | DDI_A_4_LANES);
+
 	intel_dig_port->saved_port_bits = I915_READ(DDI_BUF_CTL(port)) &
 					  (DDI_BUF_PORT_REVERSAL |
 					   DDI_A_4_LANES);
-- 
1.7.10.4