drm/radeon/dce8: properly handle interlaced timing

The register bits changed on DCE8 compared to previous
families.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/atombios_encoders.c

@@ -1962,7 +1962,13 @@ atombios_apply_encoder_quirks(struct drm_encoder *encoder,
 	/* set scaler clears this on some chips */
 	if (ASIC_IS_AVIVO(rdev) &&
 	    (!(radeon_encoder->active_device & (ATOM_DEVICE_TV_SUPPORT)))) {
-		if (ASIC_IS_DCE4(rdev)) {
+		if (ASIC_IS_DCE8(rdev)) {
+			if (mode->flags & DRM_MODE_FLAG_INTERLACE)
+				WREG32(CIK_LB_DATA_FORMAT + radeon_crtc->crtc_offset,
+				       CIK_INTERLEAVE_EN);
+			else
+				WREG32(CIK_LB_DATA_FORMAT + radeon_crtc->crtc_offset, 0);
+		} else if (ASIC_IS_DCE4(rdev)) {
 			if (mode->flags & DRM_MODE_FLAG_INTERLACE)
 				WREG32(EVERGREEN_DATA_FORMAT + radeon_crtc->crtc_offset,
 				       EVERGREEN_INTERLEAVE_EN);

drivers/gpu/drm/radeon/cik_reg.h

@@ -62,4 +62,7 @@
 #define CIK_ALPHA_CONTROL                         0x6af0
 #       define CIK_CURSOR_ALPHA_BLND_ENA          (1 << 1)
 
+#define CIK_LB_DATA_FORMAT                        0x6b00
+#       define CIK_INTERLEAVE_EN                  (1 << 3)
+
 #endif