[2/6] drm/edid: check for HF-VSDB block

Commit Message

Sharma, Shashank Feb. 1, 2017, 12:44 p.m. UTC

From: Thierry Reding <[e-mail]>

This patch implements a small function that finds if a
given CEA db is hdmi-forum vendor specific data block
or not.

Signed-off-by: Thierry Reding <[e-mail]>
---
 drivers/gpu/drm/drm_edid.c | 15 +++++++++++++++
 include/linux/hdmi.h       |  1 +
 2 files changed, 16 insertions(+)

Patch

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index baa6ccb..96d3e47 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3239,6 +3239,21 @@  static bool cea_db_is_hdmi_vsdb(const u8 *db)
 	return hdmi_id == HDMI_IEEE_OUI;
 }
 
+static bool cea_db_is_hdmi_forum_vsdb(const u8 *db)
+{
+	unsigned int oui;
+
+	if (cea_db_tag(db) != VENDOR_BLOCK)
+		return false;
+
+	if (cea_db_payload_len(db) < 7)
+		return false;
+
+	oui = db[3] << 16 | db[2] << 8 | db[1];
+
+	return oui == HDMI_FORUM_IEEE_OUI;
+}
+
 #define for_each_cea_db(cea, i, start, end) \
 	for ((i) = (start); (i) < (end) && (i) + cea_db_payload_len(&(cea)[(i)]) < (end); (i) += cea_db_payload_len(&(cea)[(i)]) + 1)
 
diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h
index edbb4fc..d271ff2 100644
--- a/include/linux/hdmi.h
+++ b/include/linux/hdmi.h
@@ -35,6 +35,7 @@  enum hdmi_infoframe_type {
 };
 
 #define HDMI_IEEE_OUI 0x000c03
+#define HDMI_FORUM_IEEE_OUI 0xc45dd8
 #define HDMI_INFOFRAME_HEADER_SIZE  4
 #define HDMI_AVI_INFOFRAME_SIZE    13
 #define HDMI_SPD_INFOFRAME_SIZE    25