[PATCH] drm/i915: Match all PSR mode entry conditions before enabling it.

[Rodrigo Vivi <rodrigo.vivi@gmail.com>]

v2: Prefer seq_puts to seq_printf by Paulo Zanoni.

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 39 ++++++++++++++++++---
 drivers/gpu/drm/i915/i915_drv.h     | 12 +++++++
 drivers/gpu/drm/i915/intel_dp.c     | 68 ++++++++++++++++++++++++++++++++++++-
 3 files changed, 114 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 67c777f..95b27ac 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1882,11 +1882,42 @@ static int i915_edp_psr_status(struct seq_file *m, void *data)
 	struct drm_info_node *node = m->private;
 	struct drm_device *dev = node->minor->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 psrctl, psrstat, psrperf;
+	u32 psrstat, psrperf;
 
-	psrctl = I915_READ(EDP_PSR_CTL);
-	seq_printf(m, "PSR Enabled: %s\n",
-		   yesno(psrctl & EDP_PSR_ENABLE));
+	if (I915_READ(EDP_PSR_CTL) & EDP_PSR_ENABLE) {
+		seq_puts(m, "PSR enabled\n");
+	} else {
+		seq_puts(m, "PSR disabled: ");
+		switch (dev_priv->no_psr_reason) {
+		case PSR_NO_SOURCE:
+			seq_puts(m, "not supported on this platform");
+			break;
+		case PSR_NO_SINK:
+			seq_puts(m, "not supported by panel");
+			break;
+		case PSR_CRTC_NOT_ACTIVE:
+			seq_puts(m, "crtc not active");
+			break;
+		case PSR_PWR_WELL_ENABLED:
+			seq_puts(m, "power well enabled");
+			break;
+		case PSR_NOT_TILED:
+			seq_puts(m, "not tiled");
+			break;
+		case PSR_SPRITE_ENABLED:
+			seq_puts(m, "sprite enabled");
+			break;
+		case PSR_INTERLACED_ENABLED:
+			seq_puts(m, "interlaced enabled");
+			break;
+		case PSR_HSW_NOT_DDIA:
+			seq_puts(m, "HSW ties PSR to DDI A (eDP)");
+			break;
+		default:
+			seq_puts(m, "unknown reason");
+		}
+		seq_puts(m, "\n");
+	}
 
 	psrstat = I915_READ(EDP_PSR_STATUS_CTL);
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 56bd82b..f08c1d9 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -543,6 +543,17 @@ enum no_fbc_reason {
 	FBC_CHIP_DEFAULT, /* disabled by default on this chip */
 };
 
+enum no_psr_reason {
+	PSR_NO_SOURCE, /* Not supported on platform */
+	PSR_NO_SINK, /* Not supported by panel */
+	PSR_CRTC_NOT_ACTIVE,
+	PSR_PWR_WELL_ENABLED,
+	PSR_NOT_TILED,
+	PSR_SPRITE_ENABLED,
+	PSR_INTERLACED_ENABLED,
+	PSR_HSW_NOT_DDIA,
+};
+
 enum intel_pch {
 	PCH_NONE = 0,	/* No PCH present */
 	PCH_IBX,	/* Ibexpeak PCH */
@@ -1146,6 +1157,7 @@ typedef struct drm_i915_private {
 	struct i915_power_well power_well;
 
 	enum no_fbc_reason no_fbc_reason;
+	enum no_psr_reason no_psr_reason;
 
 	struct drm_mm_node *compressed_fb;
 	struct drm_mm_node *compressed_llb;
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index c10be94..9730d6b 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1471,11 +1471,77 @@ static void intel_edp_psr_enable_source(struct intel_dp *intel_dp)
 		   EDP_PSR_ENABLE);
 }
 
+static bool intel_edp_psr_match_conditions(struct intel_dp *intel_dp)
+{
+	struct drm_device *dev = intel_dp_to_dev(intel_dp);
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
+	struct drm_crtc *crtc = dig_port->base.base.crtc;
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	struct drm_i915_gem_object *obj = to_intel_framebuffer(crtc->fb)->obj;
+	struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)->base;
+
+	if (!IS_HASWELL(dev)) {
+		DRM_DEBUG_KMS("PSR not supported on this platform\n");
+		dev_priv->no_psr_reason = PSR_NO_SOURCE;
+		return false;
+	}
+
+	if ((intel_encoder->type != INTEL_OUTPUT_EDP) ||
+	    (enc_to_dig_port(&intel_encoder->base)->port != PORT_A)) {
+		DRM_DEBUG_KMS("HSW ties PSR to DDI A (eDP)\n");
+		dev_priv->no_psr_reason = PSR_HSW_NOT_DDIA;
+		return false;
+	}
+
+	if (!is_edp_psr(intel_dp)) {
+		DRM_DEBUG_KMS("PSR not supported by this panel\n");
+		dev_priv->no_psr_reason = PSR_NO_SINK;
+		return false;
+	}
+
+	if (!intel_crtc->active || !crtc->fb || !crtc->mode.clock) {
+		DRM_DEBUG_KMS("crtc not active for PSR\n");
+		dev_priv->no_psr_reason = PSR_CRTC_NOT_ACTIVE;
+		return false;
+	}
+
+	if ((I915_READ(HSW_PWR_WELL_DRIVER) & HSW_PWR_WELL_ENABLE) |
+	    (I915_READ(HSW_PWR_WELL_KVMR) & HSW_PWR_WELL_ENABLE)) {
+		DRM_DEBUG_KMS("PSR condition failed: Power Well is Enabled\n");
+		dev_priv->no_psr_reason = PSR_PWR_WELL_ENABLED;
+		return false;
+	}
+
+	if (obj->tiling_mode != I915_TILING_X ||
+	    obj->fence_reg == I915_FENCE_REG_NONE) {
+		DRM_DEBUG_KMS("PSR condition failed: fb not tiled or fenced\n");
+		dev_priv->no_psr_reason = PSR_NOT_TILED;
+		return false;
+	}
+
+	if (I915_READ(SPRCTL(intel_crtc->pipe)) & SPRITE_ENABLE) {
+		DRM_DEBUG_KMS("PSR condition failed: Sprite is Enabled\n");
+		dev_priv->no_psr_reason = PSR_SPRITE_ENABLED;
+		return false;
+	}
+
+	if ((I915_READ(PIPECONF(intel_crtc->config.cpu_transcoder)) &
+	     PIPECONF_INTERLACE_MASK) == PIPECONF_INTERLACED_ILK) {
+		DRM_DEBUG_KMS("PSR condition failed: Interlaced is Enabled\n");
+		dev_priv->no_psr_reason = PSR_INTERLACED_ENABLED;
+		return false;
+	}
+
+	return true;
+}
+
 void intel_edp_psr_enable(struct intel_dp *intel_dp)
 {
 	struct drm_device *dev = intel_dp_to_dev(intel_dp);
 
-	if (!is_edp_psr(intel_dp) || intel_edp_is_psr_enabled(dev))
+	if (!intel_edp_psr_match_conditions(intel_dp) ||
+	    intel_edp_is_psr_enabled(dev))
 		return;
 
 	/* Enable PSR on the panel */
-- 
1.8.1.4