1 files changed, 45 insertions, 2 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f665b05592f3..ab6c97330412 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -598,6 +598,50 @@ struct drm_display_mode *drm_mode_std(struct drm_device *dev,
         return mode;
 }
 
+/*
+ * EDID is delightfully ambiguous about how interlaced modes are to be
+ * encoded.  Our internal representation is of frame height, but some
+ * HDTV detailed timings are encoded as field height.
+ *
+ * The format list here is from CEA, in frame size.  Technically we
+ * should be checking refresh rate too.  Whatever.
+ */
+static void
+drm_mode_do_interlace_quirk(struct drm_display_mode *mode,
+                            struct detailed_pixel_timing *pt)
+{
+        int i;
+        static const struct {
+                int w, h;
+        } cea_interlaced[] = {
+                { 1920, 1080 },
+                {  720,  480 },
+                { 1440,  480 },
+                { 2880,  480 },
+                {  720,  576 },
+                { 1440,  576 },
+                { 2880,  576 },
+        };
+        static const int n_sizes =
+                sizeof(cea_interlaced)/sizeof(cea_interlaced[0]);
+
+        if (!(pt->misc & DRM_EDID_PT_INTERLACED))
+                return;
+
+        for (i = 0; i < n_sizes; i++) {
+                if ((mode->hdisplay == cea_interlaced[i].w) &&
+                    (mode->vdisplay == cea_interlaced[i].h / 2)) {
+                        mode->vdisplay *= 2;
+                        mode->vsync_start *= 2;
+                        mode->vsync_end *= 2;
+                        mode->vtotal *= 2;
+                        mode->vtotal |= 1;
+                }
+        }
+
+        mode->flags |= DRM_MODE_FLAG_INTERLACE;
+}
+
 /**
  * drm_mode_detailed - create a new mode from an EDID detailed timing section
  * @dev: DRM device (needed to create new mode)
@@ -680,8 +724,7 @@ static struct drm_display_mode *drm_mode_detailed(struct drm_device *dev,
 
         drm_mode_set_name(mode);
 
-        if (pt->misc & DRM_EDID_PT_INTERLACED)
-                mode->flags |= DRM_MODE_FLAG_INTERLACE;
+        drm_mode_do_interlace_quirk(mode, pt);
 
         if (quirks & EDID_QUIRK_DETAILED_SYNC_PP) {
                 pt->misc |= DRM_EDID_PT_HSYNC_POSITIVE | DRM_EDID_PT_VSYNC_POSITIVE;