[Intel-gfx] [PATCH] drm/i915/vlv: reset DPIO on load and resume

[Jesse Barnes]

This fixes resume on my test platform, since I think some DPIO bits need
recalibration.

References: https://bugs.freedesktop.org/show_bug.cgi?id=69166
Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
 drivers/gpu/drm/i915/intel_display.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f52e6d4..320f729 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1359,6 +1359,17 @@ static void assert_pch_ports_disabled(struct drm_i915_private *dev_priv,
 	assert_pch_hdmi_disabled(dev_priv, pipe, PCH_HDMID);
 }
 
+static void intel_init_dpio(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (!IS_VALLEYVIEW(dev))
+		return;
+
+	/* Reset in case DPIO was stuck across suspend/resume or boot */
+	I915_WRITE(DPIO_CTL, I915_READ(DPIO_CTL) | DPIO_RESET);
+}
+
 static void vlv_enable_pll(struct intel_crtc *crtc)
 {
 	struct drm_device *dev = crtc->base.dev;
@@ -10279,6 +10290,8 @@ void intel_modeset_init_hw(struct drm_device *dev)
 {
 	intel_prepare_ddi(dev);
 
+	intel_init_dpio(dev);
+
 	intel_init_clock_gating(dev);
 
 	mutex_lock(&dev->struct_mutex);
-- 
1.8.3.1