[Intel-gfx] [PATCH v3] drm/i915: Do not enable DRRS when PSR is enabled

[Radhakrishna Sripada]

Some platforms do not support PSR and DRRS simultaneously.
Visual artifacts and flickering were reported on BDW HP Spectre
x360 Convertible. Deferring to PSR when both PSR and DRRS are
supported by the panel.

V2: Minor code-style changes suggested by Rodrigo
V3: Add a WARN_ON during PSR init suggested by Dhinakaran
    Correct debug message,title suggested by Jani

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101111
Cc: Nicholas Stommel <nicholas.stommel at gmail.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Clinton Taylor <clinton.a.taylor at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c  | 10 +++++-----
 drivers/gpu/drm/i915/intel_psr.c |  1 +
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 887953c0f495..8db6b11f103f 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5467,11 +5467,6 @@ static void intel_dp_set_drrs_state(struct drm_i915_private *dev_priv,
 		return;
 	}
 
-	/*
-	 * FIXME: This needs proper synchronization with psr state for some
-	 * platforms that cannot have PSR and DRRS enabled at the same time.
-	 */
-
 	dig_port = dp_to_dig_port(intel_dp);
 	encoder = &dig_port->base;
 	intel_crtc = to_intel_crtc(encoder->base.crtc);
@@ -5555,6 +5550,11 @@ void intel_edp_drrs_enable(struct intel_dp *intel_dp,
 		return;
 	}
 
+	if (dev_priv->psr.enabled) {
+		DRM_DEBUG_KMS("PSR enabled. Not enabling DRRS.\n");
+		return;
+	}
+
 	mutex_lock(&dev_priv->drrs.mutex);
 	if (WARN_ON(dev_priv->drrs.dp)) {
 		DRM_ERROR("DRRS already enabled\n");
diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index 55b4002bbe53..acb50945bfa8 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -530,6 +530,7 @@ void intel_psr_enable(struct intel_dp *intel_dp,
 		return;
 	}
 
+	WARN_ON(dev_priv->drrs.dp);
 	mutex_lock(&dev_priv->psr.lock);
 	if (dev_priv->psr.enabled) {
 		DRM_DEBUG_KMS("PSR already in use\n");
-- 
2.9.3