[Intel-gfx] [PATCH 06/12] drm/i915: Update intel_dp_hpd_pulse() for non-MST operation

[Todd Previte]

Update the hot plug function to handle the SST case. Instead of placing
the SST case within the long/short pulse block, it is now handled after
determining that MST mode is not in use. This way, the topology management
layer can handle any MST-related operations while SST operations are still
correctly handled afterwards.

This patch also corrects the problem of SST mode only being handled in the
case of a short (0.5ms - 1.0ms) HPD pulse. For compliance testing purposes
both short and long pulses are used by the different tests, thus both cases
need to be addressed for SST.

One additional change is the removal of the return of IRQ_HANDLED for the
SST case. This corrects an issue where the normal hot plug functions were
not being called under certain circumstances while implementing the
compliance testing.

This patch replaces [PATCH 10/10] drm/i915: Fix intel_dp_hot_plug() in the
previous compliance testing patch sequence. Review feedback on that patch
indicated that updating intel_dp_hot_plug() was not the correct place for
the test handler.

V2:
- N/A
V3:
- Place the SST mode link status check into the mst_fail case
- Remove obsolete comment regarding SST mode operation
- Removed an erroneous line of code that snuck in during rebasing
V4:
- Added a disable of the main stream (DP transport) for the long pulse case
  for SST to support compliance testing
V5:
- Reworked SST handling to support tests 4.2.2.7 and 4.2.2.8
V6:
- Reformatted a comment
V7:
- Moved a comment again that was inadvertently moved
- Updated the code to properly handle all permutations of MST/SST and
  short/long pulse.
- Adds a new 'connected' flag that prevents unnecessary operations when
  the link is disconnected.
- Added a function to encapsulate detection of the HPD pin status in
  in order to determine connected status
- Reformatted the if-statements in the function so the braces are
  consistent for those with single statements after the if-statement
- Main link disable that was added in V4 has been removed
V8:
- Updated to account for long_hpd flag propagation
V9:
- Change the return type for the SST case to IRQ_NONE to allow for
  proper invocation of other hot plug functions

Signed-off-by: Todd Previte <tprevite at gmail.com>
---
 drivers/gpu/drm/i915/intel_dp.c  | 54 ++++++++++++++++++++++++----------------
 drivers/gpu/drm/i915/intel_drv.h |  1 +
 2 files changed, 34 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 97224ff..1ba5247 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4746,6 +4746,7 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	enum intel_display_power_domain power_domain;
 	enum irqreturn ret = IRQ_NONE;
+	bool connected = false;
 
 	if (intel_dig_port->base.type != INTEL_OUTPUT_EDP)
 		intel_dig_port->base.type = INTEL_OUTPUT_DISPLAYPORT;
@@ -4769,19 +4770,15 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 	power_domain = intel_display_port_power_domain(intel_encoder);
 	intel_display_power_get(dev_priv, power_domain);
 
+	connected = intel_dp_digital_port_connected(intel_dp);
+
 	if (long_hpd) {
 
-		if (HAS_PCH_SPLIT(dev)) {
-			if (!ibx_digital_port_connected(dev_priv, intel_dig_port))
-				goto mst_fail;
-		} else {
-			if (g4x_digital_port_connected(dev, intel_dig_port) != 1)
-				goto mst_fail;
-		}
+		if (!connected)
+			goto mst_fail;
 
-		if (!intel_dp_get_dpcd(intel_dp)) {
+		if (!intel_dp_get_dpcd(intel_dp))
 			goto mst_fail;
-		}
 
 		intel_dp_probe_oui(intel_dp);
 
@@ -4789,20 +4786,9 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 			goto mst_fail;
 
 	} else {
-		if (intel_dp->is_mst) {
+		if (intel_dp->is_mst)
 			if (intel_dp_check_mst_status(intel_dp) == -EINVAL)
 				goto mst_fail;
-		}
-
-		if (!intel_dp->is_mst) {
-			/*
-			 * we'll check the link status via the normal hot plug path later -
-			 * but for short hpds we should check it now
-			 */
-			drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
-			intel_dp_check_link_status(intel_dp, long_hpd);
-			drm_modeset_unlock(&dev->mode_config.connection_mutex);
-		}
 	}
 
 	ret = IRQ_HANDLED;
@@ -4816,6 +4802,14 @@ mst_fail:
 		drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
 	}
 put_power:
+	/* SST mode - handle short/long pulses here */
+	if (!intel_dp->is_mst) {
+
+		drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+		if (connected)
+			intel_dp_check_link_status(intel_dp, long_hpd);
+		drm_modeset_unlock(&dev->mode_config.connection_mutex);
+	}
 	intel_display_power_put(dev_priv, power_domain);
 
 	return ret;
@@ -5802,3 +5796,21 @@ void intel_dp_mst_resume(struct drm_device *dev)
 		}
 	}
 }
+
+bool intel_dp_digital_port_connected(struct intel_dp *intel_dp)
+{
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	struct drm_device *dev = intel_dig_port->base.base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	bool connected = true;
+
+	if (HAS_PCH_SPLIT(dev)) {
+		if (!ibx_digital_port_connected(dev_priv, intel_dig_port))
+			connected = false;
+	} else {
+		if (g4x_digital_port_connected(dev, intel_dig_port) != 1)
+			connected = false;
+	}
+
+	return connected;
+}
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index a4675fa..accf08b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1173,6 +1173,7 @@ void intel_edp_drrs_disable(struct intel_dp *intel_dp);
 void intel_edp_drrs_invalidate(struct drm_device *dev,
 		unsigned frontbuffer_bits);
 void intel_edp_drrs_flush(struct drm_device *dev, unsigned frontbuffer_bits);
+bool intel_dp_digital_port_connected(struct intel_dp *intel_dp);
 
 /* intel_dp_mst.c */
 int intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_id);
-- 
1.9.1