drm/i915: fix ILK+ infoframe support

Misc fixes based on tests with an infoframe analyzer:
  - checksum *does* include header bytes
  - DIP enable & AVI infoframe are tied together in hw, so disable both
    and make sure AVI frames are enabled first
  - use every vsync flag for SPD frames to avoid reserved value in
    frequency field when enabling both AVI & SPD

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=40281.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@kernel.org
Signed-off-by: Keith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/intel_hdmi.c

@@ -69,8 +69,7 @@ void intel_dip_infoframe_csum(struct dip_infoframe *frame)
 	frame->checksum = 0;
 	frame->ecc = 0;
 
-	/* Header isn't part of the checksum */
-	for (i = 5; i < frame->len; i++)
+	for (i = 0; i < frame->len + DIP_HEADER_SIZE; i++)
 		sum += data[i];
 
 	frame->checksum = 0x100 - sum;
@@ -104,7 +103,7 @@ static u32 intel_infoframe_flags(struct dip_infoframe *frame)
 		flags |= VIDEO_DIP_ENABLE_AVI | VIDEO_DIP_FREQ_VSYNC;
 		break;
 	case DIP_TYPE_SPD:
-		flags |= VIDEO_DIP_ENABLE_SPD | VIDEO_DIP_FREQ_2VSYNC;
+		flags |= VIDEO_DIP_ENABLE_SPD | VIDEO_DIP_FREQ_VSYNC;
 		break;
 	default:
 		DRM_DEBUG_DRIVER("unknown info frame type %d\n", frame->type);
@@ -165,9 +164,9 @@ static void ironlake_write_infoframe(struct drm_encoder *encoder,
 
 	flags = intel_infoframe_index(frame);
 
-	val &= ~VIDEO_DIP_SELECT_MASK;
+	val &= ~(VIDEO_DIP_SELECT_MASK | 0xf); /* clear DIP data offset */
 
-	I915_WRITE(reg, val | flags);
+	I915_WRITE(reg, VIDEO_DIP_ENABLE | val | flags);
 
 	for (i = 0; i < len; i += 4) {
 		I915_WRITE(TVIDEO_DIP_DATA(intel_crtc->pipe), *data);
@@ -487,6 +486,7 @@ void intel_hdmi_init(struct drm_device *dev, int sdvox_reg)
 	struct intel_encoder *intel_encoder;
 	struct intel_connector *intel_connector;
 	struct intel_hdmi *intel_hdmi;
+	int i;
 
 	intel_hdmi = kzalloc(sizeof(struct intel_hdmi), GFP_KERNEL);
 	if (!intel_hdmi)
@@ -539,10 +539,14 @@ void intel_hdmi_init(struct drm_device *dev, int sdvox_reg)
 
 	intel_hdmi->sdvox_reg = sdvox_reg;
 
-	if (!HAS_PCH_SPLIT(dev))
+	if (!HAS_PCH_SPLIT(dev)) {
 		intel_hdmi->write_infoframe = i9xx_write_infoframe;
-	else
+		I915_WRITE(VIDEO_DIP_CTL, 0);
+	} else {
 		intel_hdmi->write_infoframe = ironlake_write_infoframe;
+		for_each_pipe(i)
+			I915_WRITE(TVIDEO_DIP_CTL(i), 0);
+	}
 
 	drm_encoder_helper_add(&intel_encoder->base, &intel_hdmi_helper_funcs);