drm/kms: Parse the detailed time info in CEA-EDID

Sometimes we can obtain the EDID with multiple blocks from the display device.
For example: HDMI monitor.
When the CEA-EDID block is detected, we should also parse the detailed timing
info from it. Otherwise we will lose some modes for the display device.

The first step is check whether the CEA EDID block is found. If it exists,
it will skip the CEA-data block and parse the detailed timing info.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_edid.c

@@ -60,6 +60,8 @@
 #define EDID_QUIRK_FIRST_DETAILED_PREFERRED	(1 << 5)
 /* use +hsync +vsync for detailed mode */
 #define EDID_QUIRK_DETAILED_SYNC_PP		(1 << 6)
+/* define the number of Extension EDID block */
+#define MAX_EDID_EXT_NUM 4
 
 #define LEVEL_DMT	0
 #define LEVEL_GTF	1
@@ -597,6 +599,122 @@ static int add_detailed_info(struct drm_connector *connector,
 
 	return modes;
 }
+/**
+ * add_detailed_mode_eedid - get detailed mode info from addtional timing
+ * 			EDID block
+ * @connector: attached connector
+ * @edid: EDID block to scan(It is only to get addtional timing EDID block)
+ * @quirks: quirks to apply
+ *
+ * Some of the detailed timing sections may contain mode information.  Grab
+ * it and add it to the list.
+ */
+static int add_detailed_info_eedid(struct drm_connector *connector,
+			     struct edid *edid, u32 quirks)
+{
+	struct drm_device *dev = connector->dev;
+	int i, j, modes = 0;
+	char *edid_ext = NULL;
+	struct detailed_timing *timing;
+	struct detailed_non_pixel *data;
+	struct drm_display_mode *newmode;
+	int edid_ext_num;
+	int start_offset, end_offset;
+	int timing_level;
+
+	if (edid->version == 1 && edid->revision < 3) {
+		/* If the EDID version is less than 1.3, there is no
+		 * extension EDID.
+		 */
+		return 0;
+	}
+	if (!edid->extensions) {
+		/* if there is no extension EDID, it is unnecessary to
+		 * parse the E-EDID to get detailed info
+		 */
+		return 0;
+	}
+
+	/* Chose real EDID extension number */
+	edid_ext_num = edid->extensions > MAX_EDID_EXT_NUM ?
+		       MAX_EDID_EXT_NUM : edid->extensions;
+
+	/* Find CEA extension */
+	for (i = 0; i < edid_ext_num; i++) {
+		edid_ext = (char *)edid + EDID_LENGTH * (i + 1);
+		/* This block is CEA extension */
+		if (edid_ext[0] == 0x02)
+			break;
+	}
+
+	if (i == edid_ext_num) {
+		/* if there is no additional timing EDID block, return */
+		return 0;
+	}
+
+	/* Get the start offset of detailed timing block */
+	start_offset = edid_ext[2];
+	if (start_offset == 0) {
+		/* If the start_offset is zero, it means that neither detailed
+		 * info nor data block exist. In such case it is also
+		 * unnecessary to parse the detailed timing info.
+		 */
+		return 0;
+	}
+
+	timing_level = standard_timing_level(edid);
+	end_offset = EDID_LENGTH;
+	end_offset -= sizeof(struct detailed_timing);
+	for (i = start_offset; i < end_offset;
+			i += sizeof(struct detailed_timing)) {
+		timing = (struct detailed_timing *)(edid_ext + i);
+		data = &timing->data.other_data;
+		/* Detailed mode timing */
+		if (timing->pixel_clock) {
+			newmode = drm_mode_detailed(dev, edid, timing, quirks);
+			if (!newmode)
+				continue;
+
+			drm_mode_probed_add(connector, newmode);
+
+			modes++;
+			continue;
+		}
+
+		/* Other timing or info */
+		switch (data->type) {
+		case EDID_DETAIL_MONITOR_SERIAL:
+			break;
+		case EDID_DETAIL_MONITOR_STRING:
+			break;
+		case EDID_DETAIL_MONITOR_RANGE:
+			/* Get monitor range data */
+			break;
+		case EDID_DETAIL_MONITOR_NAME:
+			break;
+		case EDID_DETAIL_MONITOR_CPDATA:
+			break;
+		case EDID_DETAIL_STD_MODES:
+			/* Five modes per detailed section */
+			for (j = 0; j < 5; i++) {
+				struct std_timing *std;
+				struct drm_display_mode *newmode;
+
+				std = &data->data.timings[j];
+				newmode = drm_mode_std(dev, std, timing_level);
+				if (newmode) {
+					drm_mode_probed_add(connector, newmode);
+					modes++;
+				}
+			}
+			break;
+		default:
+			break;
+		}
+	}
+
+	return modes;
+}
 
 #define DDC_ADDR 0x50
 /**
@@ -656,7 +774,6 @@ end:
 	return ret;
 }
 
-#define MAX_EDID_EXT_NUM 4
 /**
  * drm_get_edid - get EDID data, if available
  * @connector: connector we're probing
@@ -809,6 +926,7 @@ int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
 	num_modes += add_established_modes(connector, edid);
 	num_modes += add_standard_modes(connector, edid);
 	num_modes += add_detailed_info(connector, edid, quirks);
+	num_modes += add_detailed_info_eedid(connector, edid, quirks);
 
 	if (quirks & (EDID_QUIRK_PREFER_LARGE_60 | EDID_QUIRK_PREFER_LARGE_75))
 		edid_fixup_preferred(connector, quirks);