2 files changed, 15 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index e16ac5a28c3c..d5c130202396 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -569,7 +569,7 @@ void intel_crt_init(struct drm_device *dev)
                                    (1 << INTEL_ANALOG_CLONE_BIT) |
                                    (1 << INTEL_SDVO_LVDS_CLONE_BIT);
         intel_encoder->crtc_mask = (1 << 0) | (1 << 1);
-        connector->interlace_allowed = 0;
+        connector->interlace_allowed = 1;
         connector->doublescan_allowed = 0;
 
         drm_encoder_helper_add(&intel_encoder->enc, &intel_crt_helper_funcs);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 36afe9409964..4c7c151114f7 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2354,6 +2354,8 @@ static bool intel_crtc_mode_fixup(struct drm_crtc *crtc,
                 if (mode->clock * 3 > 27000 * 4)
                         return MODE_CLOCK_HIGH;
         }
+
+        drm_mode_set_crtcinfo(adjusted_mode, 0);
         return true;
 }
 
@@ -3781,6 +3783,18 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
                 }
         }
 
+        if (adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE) {
+                pipeconf |= PIPECONF_INTERLACE_W_FIELD_INDICATION;
+                /* the chip adds 2 halflines automatically */
+                adjusted_mode->crtc_vdisplay -= 1;
+                adjusted_mode->crtc_vtotal -= 1;
+                adjusted_mode->crtc_vblank_start -= 1;
+                adjusted_mode->crtc_vblank_end -= 1;
+                adjusted_mode->crtc_vsync_end -= 1;
+                adjusted_mode->crtc_vsync_start -= 1;
+        } else
+                pipeconf &= ~PIPECONF_INTERLACE_W_FIELD_INDICATION; /* progressive */
+
         I915_WRITE(htot_reg, (adjusted_mode->crtc_hdisplay - 1) |
                    ((adjusted_mode->crtc_htotal - 1) << 16));
         I915_WRITE(hblank_reg, (adjusted_mode->crtc_hblank_start - 1) |