drm/i915/bdw: Change dp aux timeout to 600us on DDIA

Cc: Art Runyan <arthur.j.runyan@intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 46837a0..3fec49b 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -405,6 +405,7 @@
 	uint32_t status;
 	int try, precharge, clock = 0;
 	bool has_aux_irq = INTEL_INFO(dev)->gen >= 5 && !IS_VALLEYVIEW(dev);
+	uint32_t timeout;
 
 	/* dp aux is extremely sensitive to irq latency, hence request the
 	 * lowest possible wakeup latency and so prevent the cpu from going into
@@ -419,6 +420,11 @@
 	else
 		precharge = 5;
 
+	if (IS_BROADWELL(dev) && ch_ctl == DPA_AUX_CH_CTL)
+		timeout = DP_AUX_CH_CTL_TIME_OUT_600us;
+	else
+		timeout = DP_AUX_CH_CTL_TIME_OUT_400us;
+
 	intel_aux_display_runtime_get(dev_priv);
 
 	/* Try to wait for any previous AUX channel activity */
@@ -454,7 +460,7 @@
 			I915_WRITE(ch_ctl,
 				   DP_AUX_CH_CTL_SEND_BUSY |
 				   (has_aux_irq ? DP_AUX_CH_CTL_INTERRUPT : 0) |
-				   DP_AUX_CH_CTL_TIME_OUT_400us |
+				   timeout |
 				   (send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
 				   (precharge << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) |
 				   (aux_clock_divider << DP_AUX_CH_CTL_BIT_CLOCK_2X_SHIFT) |