[Intel-gfx] [PATCH v2 2/5] drm/i915/psr: Tie PSR2 support to Y coordinate requirement in intel_psr_init_dpcd()

[José Roberto de Souza]

Move to only one place the sink requirements that the actual driver
needs to enable PSR2.

Also intel_psr2_config_valid() is called every time the crtc config
is computed, wasting some time every time it was checking for
Y coordinate requirement.

This allow us to nuke y_cord_support and some of VSC setup code that
was handling a scenario that would never happen(PSR2 without Y
coordinate).

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---

v2: Changes in comment requested by Rodrigo Vivi

 drivers/gpu/drm/i915/i915_drv.h  |  1 -
 drivers/gpu/drm/i915/intel_psr.c | 56 +++++++++++++++++++++-------------------
 2 files changed, 29 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 8a584273f897..d4bc8d18f56c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -603,7 +603,6 @@ struct i915_psr {
 	unsigned busy_frontbuffer_bits;
 	bool psr2_support;
 	bool link_standby;
-	bool y_cord_support;
 	bool colorimetry_support;
 	bool alpm;
 	bool has_hw_tracking;
diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index 9811f5f0bc75..5593d1f3049a 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -93,7 +93,7 @@ static void psr_aux_io_power_put(struct intel_dp *intel_dp)
 	intel_display_power_put(dev_priv, psr_aux_domain(intel_dp));
 }
 
-static bool intel_dp_get_y_cord_status(struct intel_dp *intel_dp)
+static bool intel_dp_get_y_coord_required(struct intel_dp *intel_dp)
 {
 	uint8_t psr_caps = 0;
 
@@ -137,22 +137,39 @@ void intel_psr_init_dpcd(struct intel_dp *intel_dp)
 
 	if (INTEL_GEN(dev_priv) >= 9 &&
 	    (intel_dp->psr_dpcd[0] & DP_PSR2_IS_SUPPORTED)) {
-		uint8_t frame_sync_cap;
+		uint8_t frame_sync_cap, y_coord_req;
 
 		dev_priv->psr.sink_support = true;
+
+		/* PSR2 needs frame sync to do selective updates */
 		if (drm_dp_dpcd_readb(&intel_dp->aux,
 				      DP_SINK_DEVICE_AUX_FRAME_SYNC_CAP,
 				      &frame_sync_cap) != 1)
 			frame_sync_cap = 0;
 		frame_sync_cap = (frame_sync_cap & DP_AUX_FRAME_SYNC_CAP);
-		/* PSR2 needs frame sync as well */
-		dev_priv->psr.psr2_support = frame_sync_cap;
-		DRM_DEBUG_KMS("PSR2 %s on sink",
-			      dev_priv->psr.psr2_support ? "supported" : "not supported");
+
+		/*
+		 * All panels that supports PSR version 03h (PSR2 +
+		 * Y-coordinate) support can handle Y-coordinates in VSC
+		 * but we are only sure that it is going to be used when
+		 * required by the panel. This way panel is capable to do
+		 * selective update even without a valid aux frame sync.
+		 *
+		 * To support PSR version 02h and PSR version 03h without
+		 * Y-coordinate requirement panels we would need to enable
+		 * GTC first.
+		 */
+		y_coord_req = intel_dp_get_y_coord_required(intel_dp);
+
+		dev_priv->psr.psr2_support = frame_sync_cap && y_coord_req;
+		if (dev_priv->psr.psr2_support)
+			DRM_DEBUG_KMS("PSR2 supported on sink\n");
+		else
+			DRM_DEBUG_KMS("PSR2 not supported on sink"
+				      "(frame sync: %d Y-coord required: %d)\n",
+				      frame_sync_cap, y_coord_req);
 
 		if (dev_priv->psr.psr2_support) {
-			dev_priv->psr.y_cord_support =
-				intel_dp_get_y_cord_status(intel_dp);
 			dev_priv->psr.colorimetry_support =
 				intel_dp_get_colorimetry_status(intel_dp);
 			dev_priv->psr.alpm =
@@ -198,16 +215,12 @@ static void hsw_psr_setup_vsc(struct intel_dp *intel_dp,
 		memset(&psr_vsc, 0, sizeof(psr_vsc));
 		psr_vsc.sdp_header.HB0 = 0;
 		psr_vsc.sdp_header.HB1 = 0x7;
-		if (dev_priv->psr.colorimetry_support &&
-		    dev_priv->psr.y_cord_support) {
+		if (dev_priv->psr.colorimetry_support) {
 			psr_vsc.sdp_header.HB2 = 0x5;
 			psr_vsc.sdp_header.HB3 = 0x13;
-		} else if (dev_priv->psr.y_cord_support) {
+		} else {
 			psr_vsc.sdp_header.HB2 = 0x4;
 			psr_vsc.sdp_header.HB3 = 0xe;
-		} else {
-			psr_vsc.sdp_header.HB2 = 0x3;
-			psr_vsc.sdp_header.HB3 = 0xc;
 		}
 	} else {
 		/* Prepare VSC packet as per EDP 1.3 spec, Table 3.10 */
@@ -478,15 +491,6 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
 		return false;
 	}
 
-	/*
-	 * FIXME:enable psr2 only for y-cordinate psr2 panels
-	 * After gtc implementation , remove this restriction.
-	 */
-	if (!dev_priv->psr.y_cord_support) {
-		DRM_DEBUG_KMS("PSR2 not enabled, panel does not support Y coordinate\n");
-		return false;
-	}
-
 	return true;
 }
 
@@ -586,14 +590,12 @@ static void hsw_psr_enable_source(struct intel_dp *intel_dp,
 	struct drm_device *dev = dig_port->base.base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
-	u32 chicken;
 
 	psr_aux_io_power_get(intel_dp);
 
 	if (dev_priv->psr.psr2_support) {
-		chicken = PSR2_VSC_ENABLE_PROG_HEADER;
-		if (dev_priv->psr.y_cord_support)
-			chicken |= PSR2_ADD_VERTICAL_LINE_COUNT;
+		u32 chicken = PSR2_VSC_ENABLE_PROG_HEADER
+			      | PSR2_ADD_VERTICAL_LINE_COUNT;
 		I915_WRITE(CHICKEN_TRANS(cpu_transcoder), chicken);
 
 		I915_WRITE(EDP_PSR_DEBUG,
-- 
2.16.2