[Intel-gfx] [PATCH 1/2] drm/i915: Don't vblank wait on ilk-ivb after pipe enable

[Daniel Vetter]

Like on hsw/bdw the pipe isn't actually running yet at this point.
This holds for both pch ports and the cpu edp port according to my
testing on ilk, snb and ivb.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=77297
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/intel_display.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 1aae7361b7a5..e0310e3018ee 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1827,16 +1827,6 @@ static void intel_enable_pipe(struct intel_crtc *crtc)
 
 	I915_WRITE(reg, val | PIPECONF_ENABLE);
 	POSTING_READ(reg);
-
-	/*
-	 * There's no guarantee the pipe will really start running now. It
-	 * depends on the Gen, the output type and the relative order between
-	 * pipe and plane enabling. Avoid waiting on HSW+ since it's not
-	 * necessary.
-	 * TODO: audit the previous gens.
-	 */
-	if (INTEL_INFO(dev)->gen <= 7 && !IS_HASWELL(dev))
-		intel_wait_for_vblank(dev_priv->dev, pipe);
 }
 
 /**
@@ -4461,7 +4451,9 @@ static void valleyview_crtc_enable(struct drm_crtc *crtc)
 
 	intel_update_watermarks(crtc);
 	intel_enable_pipe(intel_crtc);
+	intel_wait_for_vblank(dev_priv->dev, pipe);
 	intel_set_cpu_fifo_underrun_reporting(dev, pipe, true);
+
 	intel_enable_primary_hw_plane(dev_priv, plane, pipe);
 	intel_enable_planes(crtc);
 	intel_crtc_update_cursor(crtc, true);
@@ -4546,7 +4538,9 @@ static void i9xx_crtc_enable(struct drm_crtc *crtc)
 
 	intel_update_watermarks(crtc);
 	intel_enable_pipe(intel_crtc);
+	intel_wait_for_vblank(dev_priv->dev, pipe);
 	intel_set_cpu_fifo_underrun_reporting(dev, pipe, true);
+
 	intel_enable_primary_hw_plane(dev_priv, plane, pipe);
 	intel_enable_planes(crtc);
 	/* The fixup needs to happen before cursor is enabled */
-- 
1.8.4.rc3