drm/i915: Optimize HDCP key load

HDCP key need not be cleared on each hdcp disable. And HDCP key Load
is skipped if key is already loaded.

v2:
  No change. Added Reviewed-by tag.

v3:
  No change.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1517609350-10698-6-git-send-email-ramalingam.c@intel.com

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
index d7ddd6b28cd7..5c8e6d1829ef 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -49,6 +49,10 @@ static int intel_hdcp_load_keys(struct drm_i915_private *dev_priv)
         int ret;
         u32 val;
 
+        val = I915_READ(HDCP_KEY_STATUS);
+        if ((val & HDCP_KEY_LOAD_DONE) && (val & HDCP_KEY_LOAD_STATUS))
+                return 0;
+
         /*
          * On HSW and BDW HW loads the HDCP1.4 Key when Display comes
          * out of reset. So if Key is not already loaded, its an error state.
@@ -542,8 +546,6 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
                 return -ETIMEDOUT;
         }
 
-        intel_hdcp_clear_keys(dev_priv);
-
         ret = connector->hdcp_shim->toggle_signalling(intel_dig_port, false);
         if (ret) {
                 DRM_ERROR("Failed to disable HDCP signalling\n");