[Intel-gfx] [PATCH 11/12] drm/i915: Don't try to ack sink irqs when there are none

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

My ASUS PB278 at least doesn't seem to appreciate when you try to
ack sink irqs when there are none. Results in thus sort of dmesg spam
[drm:drm_dp_dpcd_access] too many retries, giving up

Let's skip the ack if there are no pending irqs. I have no clue why we
do this in two places. One of them likely should just go away. Oh, and
MST has its own sink irq handler too...

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 08d95352ffd6..7551d92a3cfb 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3934,7 +3934,7 @@ intel_dp_link_retrain(struct intel_dp *intel_dp)
 static bool
 intel_dp_short_pulse(struct intel_dp *intel_dp)
 {
-	u8 sink_irq_vector;
+	u8 sink_irq_vector = 0;
 	u8 old_sink_count = intel_dp->sink_count;
 	bool ret;
 
@@ -3961,7 +3961,8 @@ intel_dp_short_pulse(struct intel_dp *intel_dp)
 
 	/* Try to read the source of the interrupt */
 	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
-	    intel_dp_get_sink_irq(intel_dp, &sink_irq_vector)) {
+	    intel_dp_get_sink_irq(intel_dp, &sink_irq_vector) &&
+	    sink_irq_vector != 0) {
 		/* Clear interrupt source */
 		drm_dp_dpcd_writeb(&intel_dp->aux,
 				   DP_DEVICE_SERVICE_IRQ_VECTOR,
@@ -4227,7 +4228,7 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 	struct drm_device *dev = connector->dev;
 	enum drm_connector_status status;
 	enum intel_display_power_domain power_domain;
-	u8 sink_irq_vector;
+	u8 sink_irq_vector = 0;
 
 	power_domain = intel_display_port_aux_power_domain(intel_encoder);
 	intel_display_power_get(to_i915(dev), power_domain);
@@ -4292,7 +4293,8 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 
 	/* Try to read the source of the interrupt */
 	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
-	    intel_dp_get_sink_irq(intel_dp, &sink_irq_vector)) {
+	    intel_dp_get_sink_irq(intel_dp, &sink_irq_vector) &&
+	    sink_irq_vector != 0) {
 		/* Clear interrupt source */
 		drm_dp_dpcd_writeb(&intel_dp->aux,
 				   DP_DEVICE_SERVICE_IRQ_VECTOR,
-- 
2.7.4