[PATCH v2 04/20] drm/i915/dp: Handle a tunneling IRQ after acking it

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

From: Imre Deak <imre.deak@gmail.com>

HPD IRQs in general should be handled after acking them. The

1. Read IRQ register (read DP_DEVICE_SERVICE_IRQ_VECTOR,
   DP_LINK_SERVICE_IRQ_VECTOR_ESI0)
2. Handle IRQ
3. Ack IRQ (write DP_DEVICE_SERVICE_IRQ_VECTOR,
   DP_LINK_SERVICE_IRQ_VECTOR_ESI0)

sequence would miss a new interrupt triggered after 2. and before 3.,
since the flag set in the IRQ register for this interrupt would be
cleared in step 3.

Fix the above by handling the IRQ after acking it.

Signed-off-by: Imre Deak <imre.deak@gmail.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 27 +++++++++++--------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 9c7359057fc8b..5c1529e38a6aa 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5478,17 +5478,10 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
 
 		drm_dbg_kms(display->drm, "DPRX ESI: %4ph\n", esi);
 
-		ack[3] |= esi[3] & LINK_STATUS_CHANGED;
+		ack[3] |= esi[3] & (LINK_STATUS_CHANGED | DP_TUNNELING_IRQ);
 
 		intel_dp_mst_hpd_irq(intel_dp, esi, ack);
 
-		if (esi[3] & DP_TUNNELING_IRQ) {
-			if (drm_dp_tunnel_handle_irq(display->dp_tunnel_mgr,
-						     &intel_dp->aux))
-				reprobe_needed = true;
-			ack[3] |= DP_TUNNELING_IRQ;
-		}
-
 		if (mem_is_zero(ack, sizeof(ack)))
 			break;
 
@@ -5500,6 +5493,10 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
 
 		if ((ack[3] & LINK_STATUS_CHANGED) || intel_dp->link.force_retrain)
 			intel_dp_check_link_state(intel_dp);
+
+		if ((ack[3] & DP_TUNNELING_IRQ) &&
+		    drm_dp_tunnel_handle_irq(display->dp_tunnel_mgr, &intel_dp->aux))
+			reprobe_needed = true;
 	}
 
 	return !reprobe_needed;
@@ -5802,18 +5799,18 @@ static bool intel_dp_check_link_service_irq(struct intel_dp *intel_dp)
 			      DP_LINK_SERVICE_IRQ_VECTOR_ESI0, &val) != 1 || !val)
 		return false;
 
+	if (drm_dp_dpcd_writeb(&intel_dp->aux,
+			       DP_LINK_SERVICE_IRQ_VECTOR_ESI0, val) != 1)
+		return false;
+
+	if (val & HDMI_LINK_STATUS_CHANGED)
+		intel_dp_handle_hdmi_link_status_change(intel_dp);
+
 	if ((val & DP_TUNNELING_IRQ) &&
 	    drm_dp_tunnel_handle_irq(display->dp_tunnel_mgr,
 				     &intel_dp->aux))
 		reprobe_needed = true;
 
-	if (drm_dp_dpcd_writeb(&intel_dp->aux,
-			       DP_LINK_SERVICE_IRQ_VECTOR_ESI0, val) != 1)
-		return reprobe_needed;
-
-	if (val & HDMI_LINK_STATUS_CHANGED)
-		intel_dp_handle_hdmi_link_status_change(intel_dp);
-
 	return reprobe_needed;
 }
 
-- 
2.49.1