[PATCH] drm/bridge: dw_hdmi: don't erroneously detect HDMI displays

[Philipp Zabel]

From: Lucas Stach <l.stach at pengutronix.de>

While having a CEA mode is one prerequisite for using
HDMI transmit mode, we also have to check if the display
is actually capable of HDMI input. Fall back to DVI mode
otherwise.
This patch also gets rid of the unused local EDID copy.

Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
---
This patch is updated from
http://www.spinics.net/lists/linux-driver-devel/msg45206.html
and rebased on top of Andy Yan's "dw-hdmi: convert imx hdmi to bridge/dw_hdmi"
series.
---
 drivers/gpu/drm/bridge/dw_hdmi.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
index b88225c..58a1718 100644
--- a/drivers/gpu/drm/bridge/dw_hdmi.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi.c
@@ -27,8 +27,6 @@
 
 #include "dw_hdmi.h"
 
-#define HDMI_EDID_LEN		512
-
 #define RGB			0
 #define YCBCR444		1
 #define YCBCR422_16BITS		2
@@ -116,8 +114,8 @@ struct dw_hdmi {
 
 	int vic;
 
-	u8 edid[HDMI_EDID_LEN];
 	bool cable_plugin;
+	bool has_hdmi_monitor;
 
 	bool phy_enabled;
 	struct drm_display_mode previous_mode;
@@ -1182,13 +1180,10 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode *mode)
 
 	hdmi->vic = drm_match_cea_mode(mode);
 
-	if (!hdmi->vic) {
-		dev_dbg(hdmi->dev, "Non-CEA mode used in HDMI\n");
-		hdmi->hdmi_data.video_mode.mdvi = true;
-	} else {
-		dev_dbg(hdmi->dev, "CEA mode used vic=%d\n", hdmi->vic);
+	if (hdmi->has_hdmi_monitor && hdmi->vic)
 		hdmi->hdmi_data.video_mode.mdvi = false;
-	}
+	else
+		hdmi->hdmi_data.video_mode.mdvi = true;
 
 	if ((hdmi->vic == 6) || (hdmi->vic == 7) ||
 	    (hdmi->vic == 21) || (hdmi->vic == 22) ||
@@ -1237,7 +1232,7 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode *mode)
 	if (hdmi->hdmi_data.video_mode.mdvi) {
 		dev_dbg(hdmi->dev, "%s DVI mode\n", __func__);
 	} else {
-		dev_dbg(hdmi->dev, "%s CEA mode\n", __func__);
+		dev_dbg(hdmi->dev, "%s CEA mode VIC=%d\n", __func__, hdmi->vic);
 
 		/* HDMI Initialization Step E - Configure audio */
 		hdmi_clk_regenerator_update_pixel_clock(hdmi);
@@ -1411,9 +1406,11 @@ static int dw_hdmi_connector_get_modes(struct drm_connector *connector)
 
 		drm_mode_connector_update_edid_property(connector, edid);
 		ret = drm_add_edid_modes(connector, edid);
+		hdmi->has_hdmi_monitor = drm_detect_hdmi_monitor(edid);
 		kfree(edid);
 	} else {
 		dev_dbg(hdmi->dev, "failed to get edid\n");
+		hdmi->has_hdmi_monitor = false;
 	}
 
 	return 0;
-- 
2.1.3