[v5 6/6] 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)

v5: Remove unnecessary checks (Ville)

Cc: dri-devel at lists.freedesktop.org
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 | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 807edba4cd6f..5e915c771953 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2925,6 +2925,22 @@ static void intel_ddi_enable_fec(struct intel_encoder *encoder,
 		DRM_ERROR("Timed out waiting for FEC Enable Status\n");
 }
 
+static void intel_ddi_disable_fec_state(struct intel_encoder *encoder,
+					const struct intel_crtc_state *crtc_state)
+{
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	enum port port = encoder->port;
+	u32 val;
+
+	if (!crtc_state->fec_enable)
+		return;
+
+	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)
@@ -3063,7 +3079,9 @@ 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_crtc_state *crtc_state;
 	enum port port = encoder->port;
+
 	bool wait = false;
 	u32 val;
 
@@ -3079,6 +3097,9 @@ 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_ddi_disable_fec_state(encoder, crtc_state);
+
 	if (wait)
 		intel_wait_ddi_buf_idle(dev_priv, port);
 }
-- 
2.17.1