[PATCH 8/9] drm/i915/psr: Set the right frames values

[José Roberto de Souza]

EDP_PSR2_IDLE_FRAMES_TO_DEEP_SLEEP() was being set with the number of
frames that it should wait to enter PSR, what is wrong.
Here it is setting this field with the highest value to avoid PSR2
exits frequently, as when HW exit deep sleep it needs to go to idle
state causing a PSR exit for then waiting a few frames before
activate PSR2 again.
This will result in more power saving as the sleep state also provide
some power savings by doing selective updates instead of full screen
updates.

About EDP_PSR2_FRAMES_BEFORE_ACTIVATE() it is the number of frames
(not idle frames) that PSR2 hardware will wait to activate PSR2, so
lets keep using the sink sync latency.

Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/i915/intel_psr.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index ba7bbe3f8df2..6fd793fec5e9 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -482,13 +482,13 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
 	struct i915_psr *psr = &dev_priv->psr;
 	u32 val;
 
-	/* Let's use 6 as the minimum to cover all known cases including the
-	 * off-by-one issue that HW has in some cases.
+	/* sink_sync_latency of 8 means source has to wait for more than 8
+	 * frames, we'll go with 9 frames for now
 	 */
-	int idle_frames = max(6, dev_priv->vbt.psr.idle_frames);
+	val = EDP_PSR2_FRAMES_BEFORE_ACTIVATE(psr->sink_sync_latency + 1);
 
-	idle_frames = max(idle_frames, psr->sink_sync_latency + 1);
-	val = EDP_PSR2_IDLE_FRAMES_TO_DEEP_SLEEP(idle_frames);
+	/* Avoid deep sleep as much as possible to avoid PSR2 idle state */
+	val |= EDP_PSR2_IDLE_FRAMES_TO_DEEP_SLEEP(15);
 
 	/* FIXME: selective update is probably totally broken because it doesn't
 	 * mesh at all with our frontbuffer tracking. And the hw alone isn't
@@ -497,8 +497,6 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
 	if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv))
 		val |= EDP_Y_COORDINATE_ENABLE;
 
-	val |= EDP_PSR2_FRAMES_BEFORE_ACTIVATE(psr->sink_sync_latency + 1);
-
 	if (dev_priv->vbt.psr.tp2_tp3_wakeup_time_us >= 0 &&
 	    dev_priv->vbt.psr.tp2_tp3_wakeup_time_us <= 50)
 		val |= EDP_PSR2_TP2_TIME_50us;
-- 
2.19.1