drm/i915: Clear TX FIFO reset master override bits on chv

Clear the override bits to make sure the hardware manages
the TX FIFO reset master on its own.

v2: Squash with the earlier attempt at forcing the override bits

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_hdmi.c

@@ -1400,6 +1400,15 @@ static void chv_hdmi_pre_enable(struct intel_encoder *encoder)
 
 	mutex_lock(&dev_priv->dpio_lock);
 
+	/* allow hardware to manage TX FIFO reset source */
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS01_DW11(ch));
+	val &= ~DPIO_LANEDESKEW_STRAP_OVRD;
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS01_DW11(ch), val);
+
+	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS23_DW11(ch));
+	val &= ~DPIO_LANEDESKEW_STRAP_OVRD;
+	vlv_dpio_write(dev_priv, pipe, VLV_PCS23_DW11(ch), val);
+
 	/* Deassert soft data lane reset*/
 	val = vlv_dpio_read(dev_priv, pipe, VLV_PCS01_DW1(ch));
 	val |= CHV_PCS_REQ_SOFTRESET_EN;