[PATCH 4.8 031/125] Revert "drm/i915: Check live status before reading edid"

[Greg Kroah-Hartman]

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Weinehall <david.weinehall@xxxxxxxxxxxxxxx>

commit 23f889bdf6ee5cfff012d8b09f6bec920c691696 upstream.

This reverts commit 237ed86c693d8a8e4db476976aeb30df4deac74b.

Our current implementation of live status check (repeat 9 times
with 10ms delays between each attempt as a workaround for
buggy displays) imposes a rather serious penalty, time wise,
on intel_hdmi_detect().  Since we we already skip live status
checks on platforms before gen 7, and since we seem to have
coped quite well before the live status check was introduced
for newer platforms too, the previous behaviour is probably
preferable, at least unless someone can point to a use-case
that the live status check improves (apart from "Bspec says so".)

Signed-off-by: David Weinehall <david.weinehall@xxxxxxxxxxxxxxx>
Fixes: 237ed86c693d ("drm/i915: Check live status before reading edid")
Fixes: f8d03ea0053b ("drm/i915: increase the tries for HDMI hotplug live status checking")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97139
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94014
Acked-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Link: http://patchwork.freedesktop.org/patch/msgid/20160817124748.31208-1-david.weinehall@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/i915/intel_dp.c   |    2 -
 drivers/gpu/drm/i915/intel_drv.h  |    2 -
 drivers/gpu/drm/i915/intel_hdmi.c |   43 ++++++++------------------------------
 3 files changed, 11 insertions(+), 36 deletions(-)

--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4148,7 +4148,7 @@ static bool bxt_digital_port_connected(s
  *
  * Return %true if @port is connected, %false otherwise.
  */
-bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
+static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
 					 struct intel_digital_port *port)
 {
 	if (HAS_PCH_IBX(dev_priv))
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1388,8 +1388,6 @@ void intel_edp_drrs_disable(struct intel
 void intel_edp_drrs_invalidate(struct drm_device *dev,
 		unsigned frontbuffer_bits);
 void intel_edp_drrs_flush(struct drm_device *dev, unsigned frontbuffer_bits);
-bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
-					 struct intel_digital_port *port);
 
 void
 intel_dp_program_link_training_pattern(struct intel_dp *intel_dp,
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1422,24 +1422,22 @@ intel_hdmi_dp_dual_mode_detect(struct dr
 }
 
 static bool
-intel_hdmi_set_edid(struct drm_connector *connector, bool force)
+intel_hdmi_set_edid(struct drm_connector *connector)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);
 	struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
-	struct edid *edid = NULL;
+	struct edid *edid;
 	bool connected = false;
 
-	if (force) {
-		intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
+	intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
 
-		edid = drm_get_edid(connector,
-				    intel_gmbus_get_adapter(dev_priv,
-				    intel_hdmi->ddc_bus));
+	edid = drm_get_edid(connector,
+			    intel_gmbus_get_adapter(dev_priv,
+			    intel_hdmi->ddc_bus));
 
-		intel_hdmi_dp_dual_mode_detect(connector, edid != NULL);
+	intel_hdmi_dp_dual_mode_detect(connector, edid != NULL);
 
-		intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
-	}
+	intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
 
 	to_intel_connector(connector)->detect_edid = edid;
 	if (edid && edid->input & DRM_EDID_INPUT_DIGITAL) {
@@ -1465,37 +1463,16 @@ static enum drm_connector_status
 intel_hdmi_detect(struct drm_connector *connector, bool force)
 {
 	enum drm_connector_status status;
-	struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);
-	bool live_status = false;
-	unsigned int try;
 
 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
 		      connector->base.id, connector->name);
 
 	intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
 
-	for (try = 0; !live_status && try < 9; try++) {
-		if (try)
-			msleep(10);
-		live_status = intel_digital_port_connected(dev_priv,
-				hdmi_to_dig_port(intel_hdmi));
-	}
-
-	if (!live_status) {
-		DRM_DEBUG_KMS("HDMI live status down\n");
-		/*
-		 * Live status register is not reliable on all intel platforms.
-		 * So consider live_status only for certain platforms, for
-		 * others, read EDID to determine presence of sink.
-		 */
-		if (INTEL_INFO(dev_priv)->gen < 7 || IS_IVYBRIDGE(dev_priv))
-			live_status = true;
-	}
-
 	intel_hdmi_unset_edid(connector);
 
-	if (intel_hdmi_set_edid(connector, live_status)) {
+	if (intel_hdmi_set_edid(connector)) {
 		struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
 
 		hdmi_to_dig_port(intel_hdmi)->base.type = INTEL_OUTPUT_HDMI;
@@ -1521,7 +1498,7 @@ intel_hdmi_force(struct drm_connector *c
 	if (connector->status != connector_status_connected)
 		return;
 
-	intel_hdmi_set_edid(connector, true);
+	intel_hdmi_set_edid(connector);
 	hdmi_to_dig_port(intel_hdmi)->base.type = INTEL_OUTPUT_HDMI;
 }