[PATCH v3 13/20] drm/i915/dp: Return early if getting/acking device service IRQs fails

[Imre Deak <imre.deak@intel.com>]

If getting/acking the device service IRQs fail, the short HPD handler
should bail out, falling back to a full connector detection as in case
of any AUX access failures during the HPD handling. Do this by
separating the getting/acking and handling steps of the IRQs.

Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 37 ++++++++++++++++---------
 1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index f7e91fc16b5dd..3db2fdc78c92b 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5776,31 +5776,39 @@ void intel_dp_check_link_state(struct intel_dp *intel_dp)
  * Return %true if a full connector reprobe is required due to a failure while
  * reading or acking the device service IRQs.
  */
-static bool intel_dp_check_device_service_irq(struct intel_dp *intel_dp)
+static bool intel_dp_get_and_ack_device_service_irq(struct intel_dp *intel_dp, u8 *irq_mask)
 {
-	struct intel_display *display = to_intel_display(intel_dp);
 	u8 val;
 
+	*irq_mask = 0;
+
 	if (drm_dp_dpcd_readb(&intel_dp->aux,
 			      DP_DEVICE_SERVICE_IRQ_VECTOR, &val) != 1)
-		return true;
-
-	if (!val)
 		return false;
 
-	if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_DEVICE_SERVICE_IRQ_VECTOR, val) != 1)
+	if (!val)
 		return true;
 
-	if (val & DP_AUTOMATED_TEST_REQUEST)
+	if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_DEVICE_SERVICE_IRQ_VECTOR, val) != 1)
+		return false;
+
+	*irq_mask = val;
+
+	return true;
+}
+
+static void intel_dp_handle_device_service_irq(struct intel_dp *intel_dp, u8 irq_mask)
+{
+	struct intel_display *display = to_intel_display(intel_dp);
+
+	if (irq_mask & DP_AUTOMATED_TEST_REQUEST)
 		intel_dp_test_request(intel_dp);
 
-	if (val & DP_CP_IRQ)
+	if (irq_mask & DP_CP_IRQ)
 		intel_hdcp_handle_cp_irq(intel_dp->attached_connector);
 
-	if (val & DP_SINK_SPECIFIC_IRQ)
+	if (irq_mask & DP_SINK_SPECIFIC_IRQ)
 		drm_dbg_kms(display->drm, "Sink specific irq unhandled\n");
-
-	return false;
 }
 
 /*
@@ -5859,6 +5867,7 @@ static bool
 intel_dp_short_pulse(struct intel_dp *intel_dp)
 {
 	bool reprobe_needed = false;
+	u8 irq_mask;
 
 	intel_dp_test_reset(intel_dp);
 
@@ -5873,8 +5882,10 @@ intel_dp_short_pulse(struct intel_dp *intel_dp)
 		/* No need to proceed if we are going to do full detect */
 		return false;
 
-	if (intel_dp_check_device_service_irq(intel_dp))
-		reprobe_needed = true;
+	if (!intel_dp_get_and_ack_device_service_irq(intel_dp, &irq_mask))
+		return false;
+
+	intel_dp_handle_device_service_irq(intel_dp, irq_mask);
 
 	if (intel_dp_check_link_service_irq(intel_dp))
 		reprobe_needed = true;
-- 
2.49.1