drm/i915: Reinitialize sink scrambling/TMDS clock ratio on HPD

The LG 4k TV I have doesn't deassert HPD when I turn the TV off, but
when I turn it back on it will pulse the HPD line. By that time it has
forgotten everything we told it about scrambling and the clock ratio.
Hence if we want to get a picture out if it again we have to tell it
whether we're currently sending scrambled data or not. Implement
that via the encoder->hotplug() hook.

v2: Force a full modeset to not follow the HDMI 2.0 spec more
    closely (Shashank)

[pushed with whitespace fixes to make sparse happy]
Cc: Shashank Sharma <shashank.sharma@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180117192149.17760-1-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/intel_crt.c

@@ -956,8 +956,10 @@ void intel_crt_init(struct drm_i915_private *dev_priv)
 	crt->base.power_domain = POWER_DOMAIN_PORT_CRT;
 
 	if (I915_HAS_HOTPLUG(dev_priv) &&
-	    !dmi_check_system(intel_spurious_crt_detect))
+	    !dmi_check_system(intel_spurious_crt_detect)) {
 		crt->base.hpd_pin = HPD_CRT;
+		crt->base.hotplug = intel_encoder_hotplug;
+	}
 
 	if (HAS_DDI(dev_priv)) {
 		crt->base.port = PORT_E;

drivers/gpu/drm/i915/intel_ddi.c

@@ -25,6 +25,7 @@
  *
  */
 
+#include <drm/drm_scdc_helper.h>
 #include "i915_drv.h"
 #include "intel_drv.h"
 
@@ -2798,6 +2799,147 @@ intel_ddi_init_dp_connector(struct intel_digital_port *intel_dig_port)
 	return connector;
 }
 
+static int modeset_pipe(struct drm_crtc *crtc,
+			struct drm_modeset_acquire_ctx *ctx)
+{
+	struct drm_atomic_state *state;
+	struct drm_crtc_state *crtc_state;
+	int ret;
+
+	state = drm_atomic_state_alloc(crtc->dev);
+	if (!state)
+		return -ENOMEM;
+
+	state->acquire_ctx = ctx;
+
+	crtc_state = drm_atomic_get_crtc_state(state, crtc);
+	if (IS_ERR(crtc_state)) {
+		ret = PTR_ERR(crtc_state);
+		goto out;
+	}
+
+	crtc_state->mode_changed = true;
+
+	ret = drm_atomic_add_affected_connectors(state, crtc);
+	if (ret)
+		goto out;
+
+	ret = drm_atomic_add_affected_planes(state, crtc);
+	if (ret)
+		goto out;
+
+	ret = drm_atomic_commit(state);
+	if (ret)
+		goto out;
+
+	return 0;
+
+ out:
+	drm_atomic_state_put(state);
+
+	return ret;
+}
+
+static int intel_hdmi_reset_link(struct intel_encoder *encoder,
+				 struct drm_modeset_acquire_ctx *ctx)
+{
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	struct intel_hdmi *hdmi = enc_to_intel_hdmi(&encoder->base);
+	struct intel_connector *connector = hdmi->attached_connector;
+	struct i2c_adapter *adapter =
+		intel_gmbus_get_adapter(dev_priv, hdmi->ddc_bus);
+	struct drm_connector_state *conn_state;
+	struct intel_crtc_state *crtc_state;
+	struct intel_crtc *crtc;
+	u8 config;
+	int ret;
+
+	if (!connector || connector->base.status != connector_status_connected)
+		return 0;
+
+	ret = drm_modeset_lock(&dev_priv->drm.mode_config.connection_mutex,
+			       ctx);
+	if (ret)
+		return ret;
+
+	conn_state = connector->base.state;
+
+	crtc = to_intel_crtc(conn_state->crtc);
+	if (!crtc)
+		return 0;
+
+	ret = drm_modeset_lock(&crtc->base.mutex, ctx);
+	if (ret)
+		return ret;
+
+	crtc_state = to_intel_crtc_state(crtc->base.state);
+
+	WARN_ON(!intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI));
+
+	if (!crtc_state->base.active)
+		return 0;
+
+	if (!crtc_state->hdmi_high_tmds_clock_ratio &&
+	    !crtc_state->hdmi_scrambling)
+		return 0;
+
+	if (conn_state->commit &&
+	    !try_wait_for_completion(&conn_state->commit->hw_done))
+		return 0;
+
+	ret = drm_scdc_readb(adapter, SCDC_TMDS_CONFIG, &config);
+	if (ret < 0) {
+		DRM_ERROR("Failed to read TMDS config: %d\n", ret);
+		return 0;
+	}
+
+	if (!!(config & SCDC_TMDS_BIT_CLOCK_RATIO_BY_40) ==
+	    crtc_state->hdmi_high_tmds_clock_ratio &&
+	    !!(config & SCDC_SCRAMBLING_ENABLE) ==
+	    crtc_state->hdmi_scrambling)
+		return 0;
+
+	/*
+	 * HDMI 2.0 says that one should not send scrambled data
+	 * prior to configuring the sink scrambling, and that
+	 * TMDS clock/data transmission should be suspended when
+	 * changing the TMDS clock rate in the sink. So let's
+	 * just do a full modeset here, even though some sinks
+	 * would be perfectly happy if were to just reconfigure
+	 * the SCDC settings on the fly.
+	 */
+	return modeset_pipe(&crtc->base, ctx);
+}
+
+static bool intel_ddi_hotplug(struct intel_encoder *encoder,
+			      struct intel_connector *connector)
+{
+	struct drm_modeset_acquire_ctx ctx;
+	bool changed;
+	int ret;
+
+	changed = intel_encoder_hotplug(encoder, connector);
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+	for (;;) {
+		ret = intel_hdmi_reset_link(encoder, &ctx);
+
+		if (ret == -EDEADLK) {
+			drm_modeset_backoff(&ctx);
+			continue;
+		}
+
+		break;
+	}
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+	WARN(ret, "Acquiring modeset locks failed with %i\n", ret);
+
+	return changed;
+}
+
 static struct intel_connector *
 intel_ddi_init_hdmi_connector(struct intel_digital_port *intel_dig_port)
 {
@@ -2914,6 +3056,10 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 	drm_encoder_init(&dev_priv->drm, encoder, &intel_ddi_funcs,
 			 DRM_MODE_ENCODER_TMDS, "DDI %c", port_name(port));
 
+	if (init_hdmi)
+		intel_encoder->hotplug = intel_ddi_hotplug;
+	else
+		intel_encoder->hotplug = intel_encoder_hotplug;
 	intel_encoder->compute_output_type = intel_ddi_compute_output_type;
 	intel_encoder->compute_config = intel_ddi_compute_config;
 	intel_encoder->enable = intel_enable_ddi;

drivers/gpu/drm/i915/intel_dp.c

@@ -6393,6 +6393,7 @@ bool intel_dp_init(struct drm_i915_private *dev_priv,
 			     "DP %c", port_name(port)))
 		goto err_encoder_init;
 
+	intel_encoder->hotplug = intel_encoder_hotplug;
 	intel_encoder->compute_config = intel_dp_compute_config;
 	intel_encoder->get_hw_state = intel_dp_get_hw_state;
 	intel_encoder->get_config = intel_dp_get_config;

drivers/gpu/drm/i915/intel_drv.h

@@ -215,7 +215,8 @@ struct intel_encoder {
 	enum intel_output_type type;
 	enum port port;
 	unsigned int cloneable;
-	void (*hot_plug)(struct intel_encoder *);
+	bool (*hotplug)(struct intel_encoder *encoder,
+			struct intel_connector *connector);
 	enum intel_output_type (*compute_output_type)(struct intel_encoder *,
 						      struct intel_crtc_state *,
 						      struct drm_connector_state *);
@@ -1704,7 +1705,8 @@ int intel_dsi_dcs_init_backlight_funcs(struct intel_connector *intel_connector);
 void intel_dvo_init(struct drm_i915_private *dev_priv);
 /* intel_hotplug.c */
 void intel_hpd_poll_init(struct drm_i915_private *dev_priv);
-
+bool intel_encoder_hotplug(struct intel_encoder *encoder,
+			   struct intel_connector *connector);
 
 /* legacy fbdev emulation in intel_fbdev.c */
 #ifdef CONFIG_DRM_FBDEV_EMULATION

drivers/gpu/drm/i915/intel_hdmi.c

@@ -2383,6 +2383,7 @@ void intel_hdmi_init(struct drm_i915_private *dev_priv,
 			 &intel_hdmi_enc_funcs, DRM_MODE_ENCODER_TMDS,
 			 "HDMI %c", port_name(port));
 
+	intel_encoder->hotplug = intel_encoder_hotplug;
 	intel_encoder->compute_config = intel_hdmi_compute_config;
 	if (HAS_PCH_SPLIT(dev_priv)) {
 		intel_encoder->disable = pch_disable_hdmi;

drivers/gpu/drm/i915/intel_hotplug.c

@@ -274,24 +274,26 @@ static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 	intel_runtime_pm_put(dev_priv);
 }
 
-static bool intel_hpd_irq_event(struct drm_device *dev,
-				struct drm_connector *connector)
+bool intel_encoder_hotplug(struct intel_encoder *encoder,
+			   struct intel_connector *connector)
 {
+	struct drm_device *dev = connector->base.dev;
 	enum drm_connector_status old_status;
 
 	WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
-	old_status = connector->status;
+	old_status = connector->base.status;
 
-	connector->status = drm_helper_probe_detect(connector, NULL, false);
+	connector->base.status =
+		drm_helper_probe_detect(&connector->base, NULL, false);
 
-	if (old_status == connector->status)
+	if (old_status == connector->base.status)
 		return false;
 
 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
-		      connector->base.id,
-		      connector->name,
+		      connector->base.base.id,
+		      connector->base.name,
 		      drm_get_connector_status_name(old_status),
-		      drm_get_connector_status_name(connector->status));
+		      drm_get_connector_status_name(connector->base.status));
 
 	return true;
 }
@@ -381,10 +383,9 @@ static void i915_hotplug_work_func(struct work_struct *work)
 		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
 			DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
 				      connector->name, intel_encoder->hpd_pin);
-			if (intel_encoder->hot_plug)
-				intel_encoder->hot_plug(intel_encoder);
-			if (intel_hpd_irq_event(dev, connector))
-				changed = true;
+
+			changed |= intel_encoder->hotplug(intel_encoder,
+							  intel_connector);
 		}
 	}
 	drm_connector_list_iter_end(&conn_iter);