[PATCH v2 3/3] drm/i915: Send hotplug event if edid had changed.

[Stanislav Lisovskiy]

Added edid checking to dp and hdmi edid setting functions, which
are called from detect hooks. The result currently is propagated
to calling layer using drm_connector->change_counter(proposed by Daniel Vetter).
drm_helper_hpd_irq_event and intel_encoder_hotplug are currently both
responsible for checking if this counter or connection status is changed.

There are conflicting parts in drm and i915 which attempt
to do the same job - drm_helper_hpd_irq_event attempts to
check connector status changes and then call hotplug,
just as i915_hotplug_work_func, which calls encoder->hotplug
hook which in turn calls generic intel_encoder_hotplug function
which attempts to probe if output has changed.
Looks like both needs to be changed, so added edid checking
also to intel_encoder_hotplug function which is called both
for hdmi and dp.

v2: Renamed change counter to epoch counter. Fixed type name.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105540
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c      | 16 +++++++++++++++-
 drivers/gpu/drm/i915/display/intel_hdmi.c    | 16 +++++++++++++---
 drivers/gpu/drm/i915/display/intel_hotplug.c | 20 +++++++++++++++-----
 3 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 4336df46fe78..c2ed02478cf9 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5510,10 +5510,24 @@ static void
 intel_dp_set_edid(struct intel_dp *intel_dp)
 {
 	struct intel_connector *intel_connector = intel_dp->attached_connector;
+	struct drm_connector *connector = &intel_connector->base;
 	struct edid *edid;
+	struct edid *old_edid;
 
-	intel_dp_unset_edid(intel_dp);
 	edid = intel_dp_get_edid(intel_dp);
+	old_edid = intel_connector->detect_edid;
+
+	if (!drm_edid_are_equal(edid, old_edid)) {
+		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] Edid was changed! Updating blob property.\n",
+		    connector->base.id, connector->name);
+
+		connector->epoch_counter += 1;
+		DRM_DEBUG_KMS("Updating change counter to %llu\n", connector->epoch_counter);
+
+		intel_connector_update_modes(&intel_connector->base, edid);
+	}
+
+	intel_dp_unset_edid(intel_dp);
 	intel_connector->detect_edid = edid;
 
 	intel_dp->has_audio = drm_detect_monitor_audio(edid);
diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 0ebec69bbbfc..f892c7b795ce 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -2503,7 +2503,7 @@ 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);
 	intel_wakeref_t wakeref;
-	struct edid *edid;
+	struct edid *edid, *old_edid;
 	bool connected = false;
 	struct i2c_adapter *i2c;
 
@@ -2524,11 +2524,22 @@ intel_hdmi_set_edid(struct drm_connector *connector)
 
 	intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS, wakeref);
 
+	old_edid = to_intel_connector(connector)->detect_edid;
+
+	if (!drm_edid_are_equal(edid, old_edid)) {
+		intel_connector_update_modes(connector, edid);
+		DRM_DEBUG_KMS("Updating change counter to %llu\n", connector->epoch_counter);
+		connector->epoch_counter += 1;
+
+		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] Edid was changed! Updating blob property.\n",
+		    connector->base.id, connector->name);
+	}
+	intel_hdmi_unset_edid(connector);
 	to_intel_connector(connector)->detect_edid = edid;
+
 	if (edid && edid->input & DRM_EDID_INPUT_DIGITAL) {
 		intel_hdmi->has_audio = drm_detect_monitor_audio(edid);
 		intel_hdmi->has_hdmi_sink = drm_detect_hdmi_monitor(edid);
-
 		connected = true;
 	}
 
@@ -2555,7 +2566,6 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
 	    !intel_digital_port_connected(encoder))
 		goto out;
 
-	intel_hdmi_unset_edid(connector);
 
 	if (intel_hdmi_set_edid(connector))
 		status = connector_status_connected;
diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c
index ea3de4acc850..f9d9e963196a 100644
--- a/drivers/gpu/drm/i915/display/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/display/intel_hotplug.c
@@ -271,23 +271,33 @@ bool intel_encoder_hotplug(struct intel_encoder *encoder,
 {
 	struct drm_device *dev = connector->base.dev;
 	enum drm_connector_status old_status;
+	u64 old_epoch_counter;
+	bool ret = false;
 
 	WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 	old_status = connector->base.status;
 
+	old_epoch_counter = connector->base.epoch_counter;
+
 	connector->base.status =
 		drm_helper_probe_detect(&connector->base, NULL, false);
 
-	if (old_status == connector->base.status)
-		return false;
+	if (old_epoch_counter != connector->base.epoch_counter)
+		ret = true;
 
-	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
+	if (old_status != connector->base.status)
+		ret = true;
+
+	if (ret) {
+		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s(change counter %llu)\n",
 		      connector->base.base.id,
 		      connector->base.name,
 		      drm_get_connector_status_name(old_status),
-		      drm_get_connector_status_name(connector->base.status));
+		      drm_get_connector_status_name(connector->base.status),
+		      connector->base.epoch_counter);
+	}
 
-	return true;
+	return ret;
 }
 
 static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
-- 
2.17.1