[Intel-gfx] [PATCH 5/5] drm/i915/bdw: Add support for DRRS to switch RR

[Vandana Kannan]

For Broadwell, there is one instance of Transcoder MN values per transcoder.
For dynamic switching between multiple refreshr rates, M/N values may be
reprogrammed on the fly. Link N programming triggers update of all data and
link M & N registers and the new M/N values will be used in the next frame
that is output.

v2: Incorporated Chris's review comments
Changed to check for gen >=8 or gen > 5 before setting M/N registers

Signed-off-by: Vandana Kannan <vandana.kannan at intel.com>
Signed-off-by: Pradeep Bhat <pradeep.bhat at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c |   32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 7778808..f18a585 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -798,11 +798,20 @@ intel_dp_set_m2_n2(struct intel_crtc *crtc, struct intel_link_m_n *m_n)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	enum transcoder transcoder = crtc->config.cpu_transcoder;
 
-	I915_WRITE(PIPE_DATA_M2(transcoder),
-		TU_SIZE(m_n->tu) | m_n->gmch_m);
-	I915_WRITE(PIPE_DATA_N2(transcoder), m_n->gmch_n);
-	I915_WRITE(PIPE_LINK_M2(transcoder), m_n->link_m);
-	I915_WRITE(PIPE_LINK_N2(transcoder), m_n->link_n);
+	if (INTEL_INFO(dev)->gen >= 8) {
+		I915_WRITE(PIPE_DATA_M1(transcoder),
+			TU_SIZE(m_n->tu) | m_n->gmch_m);
+		I915_WRITE(PIPE_DATA_N1(transcoder), m_n->gmch_n);
+		I915_WRITE(PIPE_LINK_M1(transcoder), m_n->link_m);
+		I915_WRITE(PIPE_LINK_N1(transcoder), m_n->link_n);
+	} else if (INTEL_INFO(dev)->gen >= 5) {
+		I915_WRITE(PIPE_DATA_M2(transcoder),
+			TU_SIZE(m_n->tu) | m_n->gmch_m);
+		I915_WRITE(PIPE_DATA_N2(transcoder), m_n->gmch_n);
+		I915_WRITE(PIPE_LINK_M2(transcoder), m_n->link_m);
+		I915_WRITE(PIPE_LINK_N2(transcoder), m_n->link_n);
+	}
+
 	return;
 }
 
@@ -3612,8 +3621,17 @@ intel_dp_set_drrs_state(struct drm_device *dev, int refresh_rate) {
 
 	mutex_lock(&intel_dp->drrs_state.mutex);
 
-	/* Haswell and below */
-	if (INTEL_INFO(dev)->gen >= 5 && INTEL_INFO(dev)->gen < 8) {
+	if (INTEL_INFO(dev)->gen >= 8) {
+		switch (index) {
+		case DRRS_HIGH_RR:
+			intel_dp_set_m2_n2(intel_crtc, &config->dp_m_n);
+			break;
+		case DRRS_LOW_RR:
+			intel_dp_set_m2_n2(intel_crtc, &config->dp_m2_n2);
+			break;
+		};
+	} else if (INTEL_INFO(dev)->gen >= 5) {
+		/* Haswell and below */
 		reg = PIPECONF(intel_crtc->config.cpu_transcoder);
 		val = I915_READ(reg);
 		if (index > DRRS_HIGH_RR) {
-- 
1.7.9.5