[Intel-gfx] [v4 7/7] drm/i915/fec: Disable FEC state.

[Anusha Srivatsa]

Set the suitable bits in DP_TP_CTL to stop
bit correction when DSC is disabled.

v2:
- rebased.
- Add additional check for compression state. (Gaurav)

v3: rebased.

v4:
- Move the code to the proper spot according to spec (Ville)
- Use proper checks (manasi)

Cc: Gaurav K Singh <gaurav.k.singh at intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
Cc: Manasi Navare <manasi.d.navare at intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa at intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c | 32 ++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h |  2 ++
 2 files changed, 34 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index f03f44f332c7..d28280c3b299 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2915,6 +2915,31 @@ void intel_dp_enable_fec_state(struct intel_dp *intel_dp,
 		DRM_ERROR("Timed out waiting for FEC Enable Status\n");
 }
 
+void intel_dp_disable_fec_state(struct intel_dp *intel_dp,
+				const struct intel_crtc_state *crtc_state)
+{
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	enum port port = intel_dig_port->base.port;
+	u32 val;
+	u8 dsc_en_state;
+
+	if (!crtc_state->fec_enable)
+		return;
+
+	if (!crtc_state->dsc_params.compression_enable)
+		return;
+
+	drm_dp_dpcd_readb(&intel_dp->aux, DP_DSC_ENABLE, &dsc_en_state);
+
+	if (!dsc_en_state) {
+		val = I915_READ(DP_TP_CTL(port));
+		val &= ~DP_TP_CTL_FEC_ENABLE;
+		I915_WRITE(DP_TP_CTL(port), val);
+		POSTING_READ(DP_TP_CTL(port));
+	}
+}
+
 static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
 				    const struct intel_crtc_state *crtc_state,
 				    const struct drm_connector_state *conn_state)
@@ -3055,7 +3080,11 @@ static void intel_ddi_pre_enable(struct intel_encoder *encoder,
 static void intel_disable_ddi_buf(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	struct intel_digital_port *dig_port = enc_to_dig_port(&encoder->base);
+	struct intel_dp *intel_dp = &dig_port->dp;
+	struct intel_crtc_state *crtc_state;
 	enum port port = encoder->port;
+
 	bool wait = false;
 	u32 val;
 
@@ -3071,6 +3100,9 @@ static void intel_disable_ddi_buf(struct intel_encoder *encoder)
 	val |= DP_TP_CTL_LINK_TRAIN_PAT1;
 	I915_WRITE(DP_TP_CTL(port), val);
 
+	/* Disable FEC in DP Sink */
+	intel_dp_disable_fec_state(intel_dp, crtc_state);
+
 	if (wait)
 		intel_wait_ddi_buf_idle(dev_priv, port);
 }
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 1cdfa9c5da43..4ed04fad83b7 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1801,6 +1801,8 @@ void intel_dp_sink_set_fec_ready(struct intel_dp *intel_dp,
 				 int state);
 void intel_dp_enable_fec_state(struct intel_dp *intel_dp,
 			       const struct intel_crtc_state *crtc_state);
+void intel_dp_disable_fec_state(struct intel_dp *intel_dp,
+				const struct intel_crtc_state *crtc_state);
 void intel_dp_encoder_reset(struct drm_encoder *encoder);
 void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder);
 void intel_dp_encoder_destroy(struct drm_encoder *encoder);
-- 
2.17.1