1 files changed, 121 insertions, 31 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index d87f574feeca..82a4ceed3fcf 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1342,6 +1342,7 @@ MODULE_PARM_DESC(edid_fixup,
 
 static void drm_get_displayid(struct drm_connector *connector,
 			      struct edid *edid);
+static int validate_displayid(u8 *displayid, int length, int idx);
 
 static int drm_edid_block_checksum(const u8 *raw_edid)
 {
@@ -1573,6 +1574,50 @@ static void connector_bad_edid(struct drm_connector *connector,
 	}
 }
 
+/* Get override or firmware EDID */
+static struct edid *drm_get_override_edid(struct drm_connector *connector)
+{
+	struct edid *override = NULL;
+
+	if (connector->override_edid)
+		override = drm_edid_duplicate(connector->edid_blob_ptr->data);
+
+	if (!override)
+		override = drm_load_edid_firmware(connector);
+
+	return IS_ERR(override) ? NULL : override;
+}
+
+/**
+ * drm_add_override_edid_modes - add modes from override/firmware EDID
+ * @connector: connector we're probing
+ *
+ * Add modes from the override/firmware EDID, if available. Only to be used from
+ * drm_helper_probe_single_connector_modes() as a fallback for when DDC probe
+ * failed during drm_get_edid() and caused the override/firmware EDID to be
+ * skipped.
+ *
+ * Return: The number of modes added or 0 if we couldn't find any.
+ */
+int drm_add_override_edid_modes(struct drm_connector *connector)
+{
+	struct edid *override;
+	int num_modes = 0;
+
+	override = drm_get_override_edid(connector);
+	if (override) {
+		drm_connector_update_edid_property(connector, override);
+		num_modes = drm_add_edid_modes(connector, override);
+		kfree(override);
+
+		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] adding %d modes via fallback override/firmware EDID\n",
+			      connector->base.id, connector->name, num_modes);
+	}
+
+	return num_modes;
+}
+EXPORT_SYMBOL(drm_add_override_edid_modes);
+
 /**
  * drm_do_get_edid - get EDID data using a custom EDID block read function
  * @connector: connector we're probing
@@ -1600,15 +1645,10 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
 {
 	int i, j = 0, valid_extensions = 0;
 	u8 *edid, *new;
-	struct edid *override = NULL;
+	struct edid *override;
 
-	if (connector->override_edid)
-		override = drm_edid_duplicate(connector->edid_blob_ptr->data);
-
-	if (!override)
-		override = drm_load_edid_firmware(connector);
-
-	if (!IS_ERR_OR_NULL(override))
+	override = drm_get_override_edid(connector);
+	if (override)
 		return override;
 
 	if ((edid = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL)
@@ -2887,16 +2927,46 @@ static u8 *drm_find_edid_extension(const struct edid *edid, int ext_id)
 	return edid_ext;
 }
 
-static u8 *drm_find_cea_extension(const struct edid *edid)
-{
-	return drm_find_edid_extension(edid, CEA_EXT);
-}
 
 static u8 *drm_find_displayid_extension(const struct edid *edid)
 {
 	return drm_find_edid_extension(edid, DISPLAYID_EXT);
 }
 
+static u8 *drm_find_cea_extension(const struct edid *edid)
+{
+	int ret;
+	int idx = 1;
+	int length = EDID_LENGTH;
+	struct displayid_block *block;
+	u8 *cea;
+	u8 *displayid;
+
+	/* Look for a top level CEA extension block */
+	cea = drm_find_edid_extension(edid, CEA_EXT);
+	if (cea)
+		return cea;
+
+	/* CEA blocks can also be found embedded in a DisplayID block */
+	displayid = drm_find_displayid_extension(edid);
+	if (!displayid)
+		return NULL;
+
+	ret = validate_displayid(displayid, length, idx);
+	if (ret)
+		return NULL;
+
+	idx += sizeof(struct displayid_hdr);
+	for_each_displayid_db(displayid, block, idx, length) {
+		if (block->tag == DATA_BLOCK_CTA) {
+			cea = (u8 *)block;
+			break;
+		}
+	}
+
+	return cea;
+}
+
 /*
  * Calculate the alternate clock for the CEA mode
  * (60Hz vs. 59.94Hz etc.)
@@ -3620,13 +3690,38 @@ cea_revision(const u8 *cea)
 static int
 cea_db_offsets(const u8 *cea, int *start, int *end)
 {
-	/* Data block offset in CEA extension block */
-	*start = 4;
-	*end = cea[2];
-	if (*end == 0)
-		*end = 127;
-	if (*end < 4 || *end > 127)
-		return -ERANGE;
+	/* DisplayID CTA extension blocks and top-level CEA EDID
+	 * block header definitions differ in the following bytes:
+	 *   1) Byte 2 of the header specifies length differently,
+	 *   2) Byte 3 is only present in the CEA top level block.
+	 *
+	 * The different definitions for byte 2 follow.
+	 *
+	 * DisplayID CTA extension block defines byte 2 as:
+	 *   Number of payload bytes
+	 *
+	 * CEA EDID block defines byte 2 as:
+	 *   Byte number (decimal) within this block where the 18-byte
+	 *   DTDs begin. If no non-DTD data is present in this extension
+	 *   block, the value should be set to 04h (the byte after next).
+	 *   If set to 00h, there are no DTDs present in this block and
+	 *   no non-DTD data.
+	 */
+	if (cea[0] == DATA_BLOCK_CTA) {
+		*start = 3;
+		*end = *start + cea[2];
+	} else if (cea[0] == CEA_EXT) {
+		/* Data block offset in CEA extension block */
+		*start = 4;
+		*end = cea[2];
+		if (*end == 0)
+			*end = 127;
+		if (*end < 4 || *end > 127)
+			return -ERANGE;
+	} else {
+		return -ENOTSUPP;
+	}
+
 	return 0;
 }
 
@@ -4569,8 +4664,8 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi
 	 * tells us to assume 8 bpc color depth if the EDID doesn't have
 	 * extensions which tell otherwise.
 	 */
-	if ((info->bpc == 0) && (edid->revision < 4) &&
-	    (edid->input & DRM_EDID_DIGITAL_TYPE_DVI)) {
+	if (info->bpc == 0 && edid->revision == 3 &&
+	    edid->input & DRM_EDID_DIGITAL_DFP_1_X) {
 		info->bpc = 8;
 		DRM_DEBUG("%s: Assigning DFP sink color depth as %d bpc.\n",
 			  connector->name, info->bpc);
@@ -4729,11 +4824,7 @@ static int add_displayid_detailed_modes(struct drm_connector *connector,
 		return 0;
 
 	idx += sizeof(struct displayid_hdr);
-	while (block = (struct displayid_block *)&displayid[idx],
-	       idx + sizeof(struct displayid_block) <= length &&
-	       idx + sizeof(struct displayid_block) + block->num_bytes <= length &&
-	       block->num_bytes > 0) {
-		idx += block->num_bytes + sizeof(struct displayid_block);
+	for_each_displayid_db(displayid, block, idx, length) {
 		switch (block->tag) {
 		case DATA_BLOCK_TYPE_1_DETAILED_TIMING:
 			num_modes += add_displayid_detailed_1_modes(connector, block);
@@ -5350,11 +5441,7 @@ static int drm_parse_display_id(struct drm_connector *connector,
 		return ret;
 
 	idx += sizeof(struct displayid_hdr);
-	while (block = (struct displayid_block *)&displayid[idx],
-	       idx + sizeof(struct displayid_block) <= length &&
-	       idx + sizeof(struct displayid_block) + block->num_bytes <= length &&
-	       block->num_bytes > 0) {
-		idx += block->num_bytes + sizeof(struct displayid_block);
+	for_each_displayid_db(displayid, block, idx, length) {
 		DRM_DEBUG_KMS("block id 0x%x, rev %d, len %d\n",
 			      block->tag, block->rev, block->num_bytes);
 
@@ -5367,6 +5454,9 @@ static int drm_parse_display_id(struct drm_connector *connector,
 		case DATA_BLOCK_TYPE_1_DETAILED_TIMING:
 			/* handled in mode gathering code. */
 			break;
+		case DATA_BLOCK_CTA:
+			/* handled in the cea parser code. */
+			break;
 		default:
 			DRM_DEBUG_KMS("found DisplayID tag 0x%x, unhandled\n", block->tag);
 			break;