[PATCH 2/2] drm/i915/psr: Set frames before SU entry for psr2

[vathsala nagaraju]

Set frames before SU entry value for max resync frame count of
dpcd register 2009, bit field 0:3.

v2 :
 - add macro  EDP_PSR2_FRAME_BEFORE_SU (Rodrigo)
 - remove EDP_FRAMES_BEFORE_SU_ENTRY (Rodrigo)
 - add check ==1 for dpcd_read call (ville)

Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
CC: Puthikorn Voravootivat <puthik at chromium.org>
Signed-off-by: Vathsala Nagaraju <vathsala.nagaraju at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h  |  2 +-
 drivers/gpu/drm/i915/intel_psr.c | 12 ++++++++++--
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 82f36dd..89c5249 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -170,6 +170,7 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 	(mask) << 16 | (value); })
 #define _MASKED_BIT_ENABLE(a)	({ typeof(a) _a = (a); _MASKED_FIELD(_a, _a); })
 #define _MASKED_BIT_DISABLE(a)	(_MASKED_FIELD((a), 0))
+#define EDP_PSR2_FRAME_BEFORE_SU(a) ((a) << EDP_PSR2_FRAME_BEFORE_SU_SHIFT)
 
 /* Engine ID */
 
@@ -4047,7 +4048,6 @@ enum {
 #define   EDP_PSR2_FRAME_BEFORE_SU_SHIFT 4
 #define   EDP_PSR2_FRAME_BEFORE_SU_MASK	(0xf<<4)
 #define   EDP_PSR2_IDLE_MASK		0xf
-#define   EDP_FRAMES_BEFORE_SU_ENTRY   (1<<4)
 
 #define EDP_PSR2_STATUS_CTL            _MMIO(0x6f940)
 #define EDP_PSR2_STATUS_STATE_MASK     (0xf<<28)
diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index 0a17d1f..e505fa6 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -327,6 +327,7 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
 	 */
 	uint32_t idle_frames = max(6, dev_priv->vbt.psr.idle_frames);
 	uint32_t val;
+	uint8_t sink_latency;
 
 	val = idle_frames << EDP_PSR_IDLE_FRAME_SHIFT;
 
@@ -334,8 +335,15 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
 	 * mesh at all with our frontbuffer tracking. And the hw alone isn't
 	 * good enough. */
 	val |= EDP_PSR2_ENABLE |
-		EDP_SU_TRACK_ENABLE |
-		EDP_FRAMES_BEFORE_SU_ENTRY;
+		EDP_SU_TRACK_ENABLE;
+
+	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_SINK_SYNCHRONIZATION_LATENCY,
+				&sink_latency) == 1) {
+		sink_latency = sink_latency & DP_MAX_RESYNC_FRAME_CNT_MASK;
+	} else {
+		sink_latency = 0;
+	}
+	val |= EDP_PSR2_FRAME_BEFORE_SU(sink_latency + 1);
 
 	if (dev_priv->vbt.psr.tp2_tp3_wakeup_time > 5)
 		val |= EDP_PSR2_TP2_TIME_2500;
-- 
1.9.1