[Intel-gfx] [PATCH 2/3] drm/i915: Reinitialize sink scrambling/TMDS clock ratio on HPD

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

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->post_hotplug() hook.

Cc: Shashank Sharma <shashank.sharma at intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c | 75 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index f51645a08dca..12da7024f01a 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2720,6 +2720,79 @@ intel_ddi_init_dp_connector(struct intel_digital_port *intel_dig_port)
 	return connector;
 }
 
+static int intel_ddi_hdmi_reset_scrambling(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 drm_connector_state *conn_state;
+	struct intel_crtc_state *crtc_state;
+	struct intel_crtc *crtc;
+	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;
+
+	intel_hdmi_handle_sink_scrambling(encoder, &connector->base,
+					  crtc_state->hdmi_high_tmds_clock_ratio,
+					  crtc_state->hdmi_scrambling);
+
+	return 0;
+}
+
+static void intel_ddi_post_hotplug(struct intel_encoder *encoder)
+{
+	struct drm_modeset_acquire_ctx ctx;
+	int ret;
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+	for (;;) {
+		ret = intel_ddi_hdmi_reset_scrambling(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);
+}
+
 static struct intel_connector *
 intel_ddi_init_hdmi_connector(struct intel_digital_port *intel_dig_port)
 {
@@ -2830,6 +2903,8 @@ 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->post_hotplug = intel_ddi_post_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;
-- 
2.13.6