patches.baytrail/0965-drm-i915-implement-the-Haswell-mode-set-sequence-wor.patch

From ff9cee101553353772f69b775afc740c1a933e52 Mon Sep 17 00:00:00 2001
From: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date: Fri, 20 Sep 2013 16:21:19 -0300
Subject: drm/i915: implement the Haswell mode set sequence workaround
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This workaround is described in the mode set sequence documentation.
When enabling planes for the second pipe, we need to wait for 2
vblanks on the first pipe. This should solve "a flash of screen
corruption if planes are enabled on second/third pipe during the time
that big FIFO mode is exiting". Watermarks are fun :)

v2: Save indentation levels

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit e4916946b8f28dfe2c79f613cb076a5de58d79c2)
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a954c0137b53..4d2dc0b2b057 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3494,6 +3494,35 @@ static void haswell_crtc_disable_planes(struct drm_crtc *crtc)
 	intel_disable_plane(dev_priv, plane, pipe);
 }
 
+/*
+ * This implements the workaround described in the "notes" section of the mode
+ * set sequence documentation. When going from no pipes or single pipe to
+ * multiple pipes, and planes are enabled after the pipe, we need to wait at
+ * least 2 vblanks on the first pipe before enabling planes on the second pipe.
+ */
+static void haswell_mode_set_planes_workaround(struct intel_crtc *crtc)
+{
+	struct drm_device *dev = crtc->base.dev;
+	struct intel_crtc *crtc_it, *other_active_crtc = NULL;
+
+	/* We want to get the other_active_crtc only if there's only 1 other
+	 * active crtc. */
+	list_for_each_entry(crtc_it, &dev->mode_config.crtc_list, base.head) {
+		if (!crtc_it->active || crtc_it == crtc)
+			continue;
+
+		if (other_active_crtc)
+			return;
+
+		other_active_crtc = crtc_it;
+	}
+	if (!other_active_crtc)
+		return;
+
+	intel_wait_for_vblank(dev, other_active_crtc->pipe);
+	intel_wait_for_vblank(dev, other_active_crtc->pipe);
+}
+
 static void haswell_crtc_enable(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
@@ -3545,6 +3574,9 @@ static void haswell_crtc_enable(struct drm_crtc *crtc)
 		intel_opregion_notify_encoder(encoder, true);
 	}
 
+	/* If we change the relative order between pipe/planes enabling, we need
+	 * to change the workaround. */
+	haswell_mode_set_planes_workaround(intel_crtc);
 	haswell_crtc_enable_planes(crtc);
 
 	/*
-- 
1.8.5.rc3