[Intel-gfx] [v3 5/7] drm/i915/fec: Set FEC_READY in FEC_CONFIGURATION

[Anusha Srivatsa]

If the panel supports FEC, the driver has to
set the FEC_READY bit in the dpcd register:
FEC_CONFIGURATION.

This has to happen before link training.

v2: s/intel_dp_set_fec_ready/intel_dp_sink_set_fec_ready
   - change commit message. (Gaurav)

v3: rebased. (r-b Manasi)

v4: Use fec crtc state, before setting FEC_READY
bit. (Anusha)

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 |  1 +
 drivers/gpu/drm/i915/intel_dp.c  | 14 ++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h |  3 +++
 3 files changed, 18 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 1de0a3917d7f..efbada95dc4e 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2932,6 +2932,7 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
 		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
 	intel_dp_sink_set_decompression_state(intel_dp, crtc_state,
 					      DP_DECOMPRESSION_EN);
+	intel_dp_sink_set_fec_ready(intel_dp, crtc_state, DP_FEC_READY);
 	intel_dp_start_link_train(intel_dp);
 	if (port != PORT_A || INTEL_GEN(dev_priv) >= 9)
 		intel_dp_stop_link_train(intel_dp);
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 4776ce6f2174..c446821c58b2 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3057,6 +3057,20 @@ void intel_dp_sink_set_decompression_state(struct intel_dp *intel_dp,
 			      state == DP_DECOMPRESSION_EN ? "enable" : "disable");
 }
 
+void intel_dp_sink_set_fec_ready(struct intel_dp *intel_dp,
+				 const struct intel_crtc_state *crtc_state,
+				 int state)
+{
+	int ret;
+
+	if (!crtc_state->can_fec)
+		return;
+
+	ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_FEC_CONFIGURATION, state);
+	if (ret < 0)
+		DRM_DEBUG_KMS("Failed to get FEC enabled in sink\n");
+}
+
 /* If the sink supports it, try to set the power state appropriately */
 void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)
 {
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 9dac242ead12..a15ecdb4a706 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1796,6 +1796,9 @@ void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode);
 void intel_dp_sink_set_decompression_state(struct intel_dp *intel_dp,
 					   const struct intel_crtc_state *crtc_state,
 					   int state);
+void intel_dp_sink_set_fec_ready(struct intel_dp *intel_dp,
+				 const struct intel_crtc_state *crtc_state,
+				 int 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