drm/i915/psr: Cache sink synchronization latency

This value do not change overtime so better cache it than
fetch it every PSR enable.

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180328223046.16125-8-jose.souza@intel.com

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 46cae09..5373b17 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -608,6 +608,7 @@ struct i915_psr {
        bool alpm;
        bool has_hw_tracking;
        bool psr2_enabled;
+       u8 sink_sync_latency;
 
        void (*enable_source)(struct intel_dp *,
                              const struct intel_crtc_state *);

diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index bec455e..d079cf0 100644 (file)
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -122,6 +122,18 @@ static bool intel_dp_get_alpm_status(struct intel_dp *intel_dp)
        return alpm_caps & DP_ALPM_CAP;
 }
 
+static u8 intel_dp_get_sink_sync_latency(struct intel_dp *intel_dp)
+{
+       u8 val = 0;
+
+       if (drm_dp_dpcd_readb(&intel_dp->aux,
+                             DP_SYNCHRONIZATION_LATENCY_IN_SINK, &val) == 1)
+               val &= DP_MAX_RESYNC_FRAME_COUNT_MASK;
+       else
+               DRM_ERROR("Unable to get sink synchronization latency\n");
+       return val;
+}
+
 void intel_psr_init_dpcd(struct intel_dp *intel_dp)
 {
        struct drm_i915_private *dev_priv =
@@ -158,6 +170,8 @@ void intel_psr_init_dpcd(struct intel_dp *intel_dp)
                                intel_dp_get_colorimetry_status(intel_dp);
                        dev_priv->psr.alpm =
                                intel_dp_get_alpm_status(intel_dp);
+                       dev_priv->psr.sink_sync_latency =
+                               intel_dp_get_sink_sync_latency(intel_dp);
                }
        }
 }
@@ -379,10 +393,7 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
         * with the 5 or 6 idle patterns.
         */
        uint32_t idle_frames = max(6, dev_priv->vbt.psr.idle_frames);
-       uint32_t val;
-       uint8_t sink_latency;
-
-       val = idle_frames << EDP_PSR2_IDLE_FRAME_SHIFT;
+       u32 val = idle_frames << EDP_PSR2_IDLE_FRAME_SHIFT;
 
        /* FIXME: selective update is probably totally broken because it doesn't
         * mesh at all with our frontbuffer tracking. And the hw alone isn't
@@ -392,14 +403,7 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
                val |= EDP_Y_COORDINATE_VALID | EDP_Y_COORDINATE_ENABLE;
        }
 
-       if (drm_dp_dpcd_readb(&intel_dp->aux,
-                               DP_SYNCHRONIZATION_LATENCY_IN_SINK,
-                               &sink_latency) == 1) {
-               sink_latency &= DP_MAX_RESYNC_FRAME_COUNT_MASK;
-       } else {
-               sink_latency = 0;
-       }
-       val |= EDP_PSR2_FRAME_BEFORE_SU(sink_latency + 1);
+       val |= EDP_PSR2_FRAME_BEFORE_SU(dev_priv->psr.sink_sync_latency + 1);
 
        if (dev_priv->vbt.psr.tp2_tp3_wakeup_time > 5)
                val |= EDP_PSR2_TP2_TIME_2500;