[PATCH 14/22] drm/i915: add HMDI workarounds on VLV

[Jesse Barnes <jbarnes@virtuousgeek.org>]

Need to do some extra work at PLL disable time to allow HDMI to come
back up on the next mode set.
  v2: take dpio lock around update - jbarnes
      only do WA on VLV -jbarnes

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Vijay Purushothaman <vijay.a.purushothaman@intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 2bc8ce7..c0cb254 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1492,6 +1492,14 @@ static void intel_disable_pll(struct drm_i915_private *dev_priv, enum pipe pipe)
 	int reg;
 	u32 val;
 
+	if (IS_VALLEYVIEW(dev_priv->dev)) {
+		mutex_lock(&dev_priv->dpio_lock);
+		// Flicker WA for HDMI
+		intel_dpio_write(dev_priv, 0x8200, 0x00000000);
+		intel_dpio_write(dev_priv, 0x8204, 0x00e00060);
+		mutex_unlock(&dev_priv->dpio_lock);
+	}
+
 	/* Don't disable pipe A or pipe A PLLs if needed */
 	if (pipe == PIPE_A && (dev_priv->quirks & QUIRK_PIPEA_FORCE))
 		return;
@@ -4299,6 +4307,12 @@ static void vlv_update_pll(struct drm_crtc *crtc,
 	 * In Valleyview PLL and program lane counter registers are exposed
 	 * through DPIO interface
 	 */
+
+	// program DD1 Tx lane resets sets to default
+	// WA for HDMI flicker issue
+	intel_dpio_write(dev_priv, 0x8200, 0x10080);
+	intel_dpio_write(dev_priv, 0x8204, 0x00600060);
+
 	mdiv = ((bestm1 << DPIO_M1DIV_SHIFT) | (bestm2 & DPIO_M2DIV_MASK));
 	mdiv |= ((bestp1 << DPIO_P1_SHIFT) | (bestp2 << DPIO_P2_SHIFT));
 	mdiv |= ((bestn << DPIO_N_SHIFT));
-- 
1.7.9.5