drm/mode: get the modeline for standard timing in EDID by using CVT/GTF

Create the standard timing modeline by using CVT/GFT algorithm while
interpreting the EDID.

In course of interpreting the EDID, the timing level will be obtained,
which is used to determine whether the CVT/GTF algorithm is selected to
generate the modeline for the given hdisplay/vdisplay/vrefresh_rate.
In the UMS mode firstly it will check whether it can be found in
the DMT table. If it can be found, then the modeline is returned. Then the
timing_level is used to choose CVT/GTF.
As there is no DMT table, no modeline is returned when timing level
is DMT. For the other two timing levels, the CVT/GTF will be called to
generate the required standard timing modeline.

[airlied: fixed up conflicts since EDID rework]

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>

1 files changed, 58 insertions, 12 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 80cc6d06d61b..bbcb2e22675b 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -61,6 +61,10 @@
 /* use +hsync +vsync for detailed mode */
 #define EDID_QUIRK_DETAILED_SYNC_PP             (1 << 6)
 
+#define LEVEL_DMT       0
+#define LEVEL_GTF       1
+#define LEVEL_CVT       2
+
 static struct edid_quirk {
         char *vendor;
         int product_id;
@@ -240,25 +244,31 @@ static void edid_fixup_preferred(struct drm_connector *connector,
 /**
  * drm_mode_std - convert standard mode info (width, height, refresh) into mode
  * @t: standard timing params
+ * @timing_level: standard timing level
  *
  * Take the standard timing params (in this case width, aspect, and refresh)
- * and convert them into a real mode using CVT.
+ * and convert them into a real mode using CVT/GTF/DMT.
  *
  * Punts for now, but should eventually use the FB layer's CVT based mode
  * generation code.
  */
 struct drm_display_mode *drm_mode_std(struct drm_device *dev,
-                                      struct std_timing *t)
+                                      struct std_timing *t,
+                                      int timing_level)
 {
         struct drm_display_mode *mode;
-        int hsize = t->hsize * 8 + 248, vsize;
+        int hsize, vsize;
+        int vrefresh_rate;
         unsigned aspect_ratio = (t->vfreq_aspect & EDID_TIMING_ASPECT_MASK)
                 >> EDID_TIMING_ASPECT_SHIFT;
-
-        mode = drm_mode_create(dev);
-        if (!mode)
-                return NULL;
-
+        unsigned vfreq = (t->vfreq_aspect & EDID_TIMING_VFREQ_MASK)
+                >> EDID_TIMING_VFREQ_SHIFT;
+
+        /* According to the EDID spec, the hdisplay = hsize * 8 + 248 */
+        hsize = t->hsize * 8 + 248;
+        /* vrefresh_rate = vfreq + 60 */
+        vrefresh_rate = vfreq + 60;
+        /* the vdisplay is calculated based on the aspect ratio */
         if (aspect_ratio == 0)
                 vsize = (hsize * 10) / 16;
         else if (aspect_ratio == 1)
@@ -268,8 +278,23 @@ struct drm_display_mode *drm_mode_std(struct drm_device *dev,
         else
                 vsize = (hsize * 9) / 16;
 
-        drm_mode_set_name(mode);
-
+        mode = NULL;
+        switch (timing_level) {
+        case LEVEL_DMT:
+                mode = drm_mode_create(dev);
+                if (mode) {
+                        mode->hdisplay = hsize;
+                        mode->vdisplay = vsize;
+                        drm_mode_set_name(mode);
+                }
+                break;
+        case LEVEL_GTF:
+                mode = drm_gtf_mode(dev, hsize, vsize, vrefresh_rate, 0, 0);
+                break;
+        case LEVEL_CVT:
+                mode = drm_cvt_mode(dev, hsize, vsize, vrefresh_rate, 0, 0);
+                break;
+        }
         return mode;
 }
 
@@ -451,6 +476,19 @@ static int add_established_modes(struct drm_connector *connector, struct edid *e
 
         return modes;
 }
+/**
+ * stanard_timing_level - get std. timing level(CVT/GTF/DMT)
+ * @edid: EDID block to scan
+ */
+static int standard_timing_level(struct edid *edid)
+{
+        if (edid->revision >= 2) {
+                if (edid->revision >= 4 && (edid->features & DRM_EDID_FEATURE_DEFAULT_GTF))
+                        return LEVEL_CVT;
+                return LEVEL_GTF;
+        }
+        return LEVEL_DMT;
+}
 
 /**
  * add_standard_modes - get std. modes from EDID and add them
@@ -463,6 +501,9 @@ static int add_standard_modes(struct drm_connector *connector, struct edid *edid
 {
         struct drm_device *dev = connector->dev;
         int i, modes = 0;
+        int timing_level;
+
+        timing_level = standard_timing_level(edid);
 
         for (i = 0; i < EDID_STD_TIMINGS; i++) {
                 struct std_timing *t = &edid->standard_timings[i];
@@ -472,7 +513,8 @@ static int add_standard_modes(struct drm_connector *connector, struct edid *edid
                 if (t->hsize == 1 && t->vfreq_aspect == 1)
                         continue;
 
-                newmode = drm_mode_std(dev, &edid->standard_timings[i]);
+                newmode = drm_mode_std(dev, &edid->standard_timings[i],
+                                        timing_level);
                 if (newmode) {
                         drm_mode_probed_add(connector, newmode);
                         modes++;
@@ -496,6 +538,9 @@ static int add_detailed_info(struct drm_connector *connector,
 {
         struct drm_device *dev = connector->dev;
         int i, j, modes = 0;
+        int timing_level;
+
+        timing_level = standard_timing_level(edid);
 
         for (i = 0; i < EDID_DETAILED_TIMINGS; i++) {
                 struct detailed_timing *timing = &edid->detailed_timings[i];
@@ -541,7 +586,8 @@ static int add_detailed_info(struct drm_connector *connector,
                                 struct drm_display_mode *newmode;
 
                                 std = &data->data.timings[j];
-                                newmode = drm_mode_std(dev, std);
+                                newmode = drm_mode_std(dev, std,
+                                                        timing_level);
                                 if (newmode) {
                                         drm_mode_probed_add(connector, newmode);
                                         modes++;