drm/i915: Fix RGB color range property for PCH platforms

The RGB color range select bit on the DP/SDVO/HDMI registers
disappeared when PCH was introduced, and instead a new PIPECONF bit
was added that performs the same function.

Add a new INTEL_MODE_LIMITED_COLOR_RANGE private mode flag, and set
it in the encoder mode_fixup if limited color range is requested.
Set the the PIPECONF bit 13 based on the flag.

Experimentation showed that simply toggling the bit while the pipe is
active doesn't work. We need to restart the pipe, which luckily already
happens.

The DP/SDVO/HDMI bit 8 is marked MBZ in the docs, so avoid setting it,
although it doesn't seem to do any harm in practice.

TODO:
- the PIPECONF bit too seems to have disappeared from HSW. Need a
  volunteer to test if it's just a documentation issue or if it's really
  gone. If the bit is gone and no easy replacement is found, then I suppose
  we may need to use the pipe CSC unit to perform the range compression.

v2: Use mode private_flags instead of intel_encoder virtual functions
v3: Moved the intel_dp color_range handling after bpc check to help
    later patches

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=46800
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 4c33bd2..2521617 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2650,6 +2650,7 @@
 #define   PIPECONF_INTERLACED_DBL_ILK		(4 << 21) /* ilk/snb only */
 #define   PIPECONF_PFIT_PF_INTERLACED_DBL_ILK	(5 << 21) /* ilk/snb only */
 #define   PIPECONF_CXSR_DOWNCLOCK	(1<<16)
+#define   PIPECONF_COLOR_RANGE_SELECT	(1 << 13)
 #define   PIPECONF_BPC_MASK	(0x7 << 5)
 #define   PIPECONF_8BPC		(0<<5)
 #define   PIPECONF_10BPC	(1<<5)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e4c5067..b35902e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5096,6 +5096,11 @@
 	else
 		val |= PIPECONF_PROGRESSIVE;
 
+	if (adjusted_mode->private_flags & INTEL_MODE_LIMITED_COLOR_RANGE)
+		val |= PIPECONF_COLOR_RANGE_SELECT;
+	else
+		val &= ~PIPECONF_COLOR_RANGE_SELECT;
+
 	I915_WRITE(PIPECONF(pipe), val);
 	POSTING_READ(PIPECONF(pipe));
 }
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 5f12eb2..d995627 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -763,6 +763,10 @@
 		return false;
 
 	bpp = adjusted_mode->private_flags & INTEL_MODE_DP_FORCE_6BPC ? 18 : 24;
+
+	if (intel_dp->color_range)
+		adjusted_mode->private_flags |= INTEL_MODE_LIMITED_COLOR_RANGE;
+
 	mode_rate = intel_dp_link_required(adjusted_mode->clock, bpp);
 
 	for (clock = 0; clock <= max_clock; clock++) {
@@ -967,7 +971,8 @@
 		else
 			intel_dp->DP |= DP_PLL_FREQ_270MHZ;
 	} else if (!HAS_PCH_CPT(dev) || is_cpu_edp(intel_dp)) {
-		intel_dp->DP |= intel_dp->color_range;
+		if (!HAS_PCH_SPLIT(dev))
+			intel_dp->DP |= intel_dp->color_range;
 
 		if (adjusted_mode->flags & DRM_MODE_FLAG_PHSYNC)
 			intel_dp->DP |= DP_SYNC_HS_HIGH;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 54a034c..4df47be 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -109,6 +109,11 @@
  * timings in the mode to prevent the crtc fixup from overwriting them.
  * Currently only lvds needs that. */
 #define INTEL_MODE_CRTC_TIMINGS_SET (0x20)
+/*
+ * Set when limited 16-235 (as opposed to full 0-255) RGB color range is
+ * to be used.
+ */
+#define INTEL_MODE_LIMITED_COLOR_RANGE (0x40)
 
 static inline void
 intel_mode_set_pixel_multiplier(struct drm_display_mode *mode,
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 6387f9b..f194d75 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -766,6 +766,11 @@
 			   const struct drm_display_mode *mode,
 			   struct drm_display_mode *adjusted_mode)
 {
+	struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(encoder);
+
+	if (intel_hdmi->color_range)
+		adjusted_mode->private_flags |= INTEL_MODE_LIMITED_COLOR_RANGE;
+
 	return true;
 }
 
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 153377b..3b8491a 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -1064,6 +1064,9 @@
 	multiplier = intel_sdvo_get_pixel_multiplier(adjusted_mode);
 	intel_mode_set_pixel_multiplier(adjusted_mode, multiplier);
 
+	if (intel_sdvo->color_range)
+		adjusted_mode->private_flags |= INTEL_MODE_LIMITED_COLOR_RANGE;
+
 	return true;
 }
 
@@ -1153,7 +1156,7 @@
 		/* The real mode polarity is set by the SDVO commands, using
 		 * struct intel_sdvo_dtd. */
 		sdvox = SDVO_VSYNC_ACTIVE_HIGH | SDVO_HSYNC_ACTIVE_HIGH;
-		if (intel_sdvo->is_hdmi)
+		if (!HAS_PCH_SPLIT(dev) && intel_sdvo->is_hdmi)
 			sdvox |= intel_sdvo->color_range;
 		if (INTEL_INFO(dev)->gen < 5)
 			sdvox |= SDVO_BORDER_ENABLE;