drm/i915: Add HSW CRT output readout support

Call intel_ddi_get_config() to get the pipe_bpp settings from
DDI.

The sync polarity settings from DDI are irrelevant for CRT
output, so override them with data from the ADPA register.

Note: This is already merged in drm-intel-next-queued as

commit 6801c18c0a
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Tue Sep 24 14:24:05 2013 +0300

    drm/i915: Add HSW CRT output readout support

but is required for the following edp bpp bugfix.

v2: Extract intel_crt_get_flags()

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=69691
Tested-by: Qingshuai Tian <qingshuai.tian@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_crt.c

@@ -83,8 +83,7 @@ static bool intel_crt_get_hw_state(struct intel_encoder *encoder,
 	return true;
 }
 
-static void intel_crt_get_config(struct intel_encoder *encoder,
-				 struct intel_crtc_config *pipe_config)
+static unsigned int intel_crt_get_flags(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	struct intel_crt *crt = intel_encoder_to_crt(encoder);
@@ -102,7 +101,27 @@ static void intel_crt_get_config(struct intel_encoder *encoder,
 	else
 		flags |= DRM_MODE_FLAG_NVSYNC;
 
-	pipe_config->adjusted_mode.flags |= flags;
+	return flags;
+}
+
+static void intel_crt_get_config(struct intel_encoder *encoder,
+				 struct intel_crtc_config *pipe_config)
+{
+	struct drm_device *dev = encoder->base.dev;
+
+	pipe_config->adjusted_mode.flags |= intel_crt_get_flags(encoder);
+}
+
+static void hsw_crt_get_config(struct intel_encoder *encoder,
+			       struct intel_crtc_config *pipe_config)
+{
+	intel_ddi_get_config(encoder, pipe_config);
+
+	pipe_config->adjusted_mode.flags &= ~(DRM_MODE_FLAG_PHSYNC |
+					      DRM_MODE_FLAG_NHSYNC |
+					      DRM_MODE_FLAG_PVSYNC |
+					      DRM_MODE_FLAG_NVSYNC);
+	pipe_config->adjusted_mode.flags |= intel_crt_get_flags(encoder);
 }
 
 /* Note: The caller is required to filter out dpms modes not supported by the
@@ -799,7 +818,10 @@ void intel_crt_init(struct drm_device *dev)
 	crt->base.mode_set = intel_crt_mode_set;
 	crt->base.disable = intel_disable_crt;
 	crt->base.enable = intel_enable_crt;
-	crt->base.get_config = intel_crt_get_config;
+	if (IS_HASWELL(dev))
+		crt->base.get_config = hsw_crt_get_config;
+	else
+		crt->base.get_config = intel_crt_get_config;
 	if (I915_HAS_HOTPLUG(dev))
 		crt->base.hpd_pin = HPD_CRT;
 	if (HAS_DDI(dev))

drivers/gpu/drm/i915/intel_ddi.c

@@ -1249,8 +1249,8 @@ static void intel_ddi_hot_plug(struct intel_encoder *intel_encoder)
 		intel_dp_check_link_status(intel_dp);
 }
 
-static void intel_ddi_get_config(struct intel_encoder *encoder,
-				 struct intel_crtc_config *pipe_config)
+void intel_ddi_get_config(struct intel_encoder *encoder,
+			  struct intel_crtc_config *pipe_config)
 {
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);

drivers/gpu/drm/i915/intel_drv.h

@@ -765,6 +765,8 @@ extern void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder);
 extern bool
 intel_ddi_connector_get_hw_state(struct intel_connector *intel_connector);
 extern void intel_ddi_fdi_disable(struct drm_crtc *crtc);
+extern void intel_ddi_get_config(struct intel_encoder *encoder,
+				 struct intel_crtc_config *pipe_config);
 
 extern void intel_display_handle_reset(struct drm_device *dev);
 extern bool intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev,