drm/i915: Increase timeout for Encrypt status change

At enable/disable of the HDCP encryption, for encryption status change
we need minimum one frame duration. And we might program this bit any
point(start/End) in the previous frame.

With 20mSec, observed the timeout for change in encryption status.
Since this is not time critical operation and we need to hold on
until the status is changed, fixing the timeout to 50mSec. (Based on
trial and error method!)

v2:
  %s/TIME_FOR_ENCRYPT_STATUS_CHANGE/ENCRYPT_STATUS_CHANGE_TIMEOUT_MS
	[Sean Paul]
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1544010283-20223-5-git-send-email-ramalingam.c@intel.com

drivers/gpu/drm/i915/intel_hdcp.c

@@ -15,6 +15,7 @@
 #include "i915_reg.h"
 
 #define KEY_LOAD_TRIES	5
+#define ENCRYPT_STATUS_CHANGE_TIMEOUT_MS	50
 
 static
 bool intel_hdcp_is_ksv_valid(u8 *ksv)
@@ -637,7 +638,8 @@ static int intel_hdcp_auth(struct intel_digital_port *intel_dig_port,
 
 	/* Wait for encryption confirmation */
 	if (intel_wait_for_register(dev_priv, PORT_HDCP_STATUS(port),
-				    HDCP_STATUS_ENC, HDCP_STATUS_ENC, 20)) {
+				    HDCP_STATUS_ENC, HDCP_STATUS_ENC,
+				    ENCRYPT_STATUS_CHANGE_TIMEOUT_MS)) {
 		DRM_ERROR("Timed out waiting for encryption\n");
 		return -ETIMEDOUT;
 	}
@@ -667,7 +669,7 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
 
 	I915_WRITE(PORT_HDCP_CONF(port), 0);
 	if (intel_wait_for_register(dev_priv, PORT_HDCP_STATUS(port), ~0, 0,
-				    20)) {
+				    ENCRYPT_STATUS_CHANGE_TIMEOUT_MS)) {
 		DRM_ERROR("Failed to disable HDCP, timeout clearing status\n");
 		return -ETIMEDOUT;
 	}