[PATCH v4 3/4] drm/i915: debug log for REPLY_ACK missing

[Ramalingam C <ramalingam.c@intel.com>]

Adding a debug log when the DP_AUX_NATIVE_REPLY_ACK is missing
for aksv write. This helps to locate the possible non responding
DP HDCP sinks.

v2:
  Rewritten for readability [Sean Paul]

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Sean Paul <sean@poorly.run>
---
 drivers/gpu/drm/i915/intel_dp.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 38a6e82153fd..9f75ca04a344 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5579,7 +5579,12 @@ int intel_dp_hdcp_write_an_aksv(struct intel_digital_port *intel_dig_port,
 	}
 
 	reply = (rxbuf[0] >> 4) & DP_AUX_NATIVE_REPLY_MASK;
-	return reply == DP_AUX_NATIVE_REPLY_ACK ? 0 : -EIO;
+	if (reply != DP_AUX_NATIVE_REPLY_ACK) {
+		DRM_DEBUG_KMS("Aksv write: no DP_AUX_NATIVE_REPLY_ACK %x\n",
+			      reply);
+		return -EIO;
+	}
+	return 0;
 }
 
 static int intel_dp_hdcp_read_bksv(struct intel_digital_port *intel_dig_port,
-- 
2.7.4

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