drm/edid: Expose mandatory stereo modes for HDMI sinks

For now, let's just look at the 3D_present flag of the CEA HDMI vendor
block to detect if the sink supports a small list of then mandatory 3D
formats.

See the HDMI 1.4a 3D extraction for detail:
  http://www.hdmi.org/manufacturer/specification.aspx

v2: Rename freq to vrefresh, make the mandatory structure a bit more
    compact, fix some white space issues and add a couple of const
    (Ville Syrjälä)

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 103 insertions, 7 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 1688ff500513..52e60879149b 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2553,13 +2553,95 @@ do_cea_modes(struct drm_connector *connector, const u8 *db, u8 len)
         return modes;
 }
 
+struct stereo_mandatory_mode {
+        int width, height, vrefresh;
+        unsigned int flags;
+};
+
+static const struct stereo_mandatory_mode stereo_mandatory_modes[] = {
+        { 1920, 1080, 24,
+          DRM_MODE_FLAG_3D_TOP_AND_BOTTOM | DRM_MODE_FLAG_3D_FRAME_PACKING },
+        { 1920, 1080, 50,
+          DRM_MODE_FLAG_INTERLACE | DRM_MODE_FLAG_3D_SIDE_BY_SIDE_HALF },
+        { 1920, 1080, 60,
+          DRM_MODE_FLAG_INTERLACE | DRM_MODE_FLAG_3D_SIDE_BY_SIDE_HALF },
+        { 1280, 720,  50,
+          DRM_MODE_FLAG_3D_TOP_AND_BOTTOM | DRM_MODE_FLAG_3D_FRAME_PACKING },
+        { 1280, 720,  60,
+          DRM_MODE_FLAG_3D_TOP_AND_BOTTOM | DRM_MODE_FLAG_3D_FRAME_PACKING }
+};
+
+static bool
+stereo_match_mandatory(const struct drm_display_mode *mode,
+                       const struct stereo_mandatory_mode *stereo_mode)
+{
+        unsigned int interlaced = mode->flags & DRM_MODE_FLAG_INTERLACE;
+
+        return mode->hdisplay == stereo_mode->width &&
+               mode->vdisplay == stereo_mode->height &&
+               interlaced == (stereo_mode->flags & DRM_MODE_FLAG_INTERLACE) &&
+               drm_mode_vrefresh(mode) == stereo_mode->vrefresh;
+}
+
+static const struct stereo_mandatory_mode *
+hdmi_find_stereo_mandatory_mode(const struct drm_display_mode *mode)
+{
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(stereo_mandatory_modes); i++)
+                if (stereo_match_mandatory(mode, &stereo_mandatory_modes[i]))
+                        return &stereo_mandatory_modes[i];
+
+        return NULL;
+}
+
+static int add_hdmi_mandatory_stereo_modes(struct drm_connector *connector)
+{
+        struct drm_device *dev = connector->dev;
+        const struct drm_display_mode *mode;
+        struct list_head stereo_modes;
+        int modes = 0;
+
+        INIT_LIST_HEAD(&stereo_modes);
+
+        list_for_each_entry(mode, &connector->probed_modes, head) {
+                const struct stereo_mandatory_mode *mandatory;
+                u32 stereo_layouts, layout;
+
+                mandatory = hdmi_find_stereo_mandatory_mode(mode);
+                if (!mandatory)
+                        continue;
+
+                stereo_layouts = mandatory->flags & DRM_MODE_FLAG_3D_MASK;
+                do {
+                        struct drm_display_mode *new_mode;
+
+                        layout = 1 << (ffs(stereo_layouts) - 1);
+                        stereo_layouts &= ~layout;
+
+                        new_mode = drm_mode_duplicate(dev, mode);
+                        if (!new_mode)
+                                continue;
+
+                        new_mode->flags |= layout;
+                        list_add_tail(&new_mode->head, &stereo_modes);
+                        modes++;
+                } while (stereo_layouts);
+        }
+
+        list_splice_tail(&stereo_modes, &connector->probed_modes);
+
+        return modes;
+}
+
 /*
  * do_hdmi_vsdb_modes - Parse the HDMI Vendor Specific data block
  * @connector: connector corresponding to the HDMI sink
  * @db: start of the CEA vendor specific block
  * @len: length of the CEA block payload, ie. one can access up to db[len]
  *
- * Parses the HDMI VSDB looking for modes to add to @connector.
+ * Parses the HDMI VSDB looking for modes to add to @connector. This function
+ * also adds the stereo 3d modes when applicable.
  */
 static int
 do_hdmi_vsdb_modes(struct drm_connector *connector, const u8 *db, u8 len)
@@ -2585,10 +2667,15 @@ do_hdmi_vsdb_modes(struct drm_connector *connector, const u8 *db, u8 len)
 
         /* the declared length is not long enough for the 2 first bytes
          * of additional video format capabilities */
-        offset += 2;
-        if (len < (8 + offset))
+        if (len < (8 + offset + 2))
                 goto out;
 
+        /* 3D_Present */
+        offset++;
+        if (db[8 + offset] & (1 << 7))
+                modes += add_hdmi_mandatory_stereo_modes(connector);
+
+        offset++;
         vic_len = db[8 + offset] >> 5;
 
         for (i = 0; i < vic_len && len >= (9 + offset + i); i++) {
@@ -2668,8 +2755,8 @@ static int
 add_cea_modes(struct drm_connector *connector, struct edid *edid)
 {
         const u8 *cea = drm_find_cea_extension(edid);
-        const u8 *db;
-        u8 dbl;
+        const u8 *db, *hdmi = NULL;
+        u8 dbl, hdmi_len;
         int modes = 0;
 
         if (cea && cea_revision(cea) >= 3) {
@@ -2684,11 +2771,20 @@ add_cea_modes(struct drm_connector *connector, struct edid *edid)
 
                         if (cea_db_tag(db) == VIDEO_BLOCK)
                                 modes += do_cea_modes(connector, db + 1, dbl);
-                        else if (cea_db_is_hdmi_vsdb(db))
-                                modes += do_hdmi_vsdb_modes(connector, db, dbl);
+                        else if (cea_db_is_hdmi_vsdb(db)) {
+                                hdmi = db;
+                                hdmi_len = dbl;
+                        }
                 }
         }
 
+        /*
+         * We parse the HDMI VSDB after having added the cea modes as we will
+         * be patching their flags when the sink supports stereo 3D.
+         */
+        if (hdmi)
+                modes += do_hdmi_vsdb_modes(connector, hdmi, hdmi_len);
+
         return modes;
 }