drm/i915: Markup paired operations on display power domains

The majority of runtime-pm operations are bounded and scoped within a
function; these are easy to verify that the wakeref are handled
correctly. We can employ the compiler to help us, and reduce the number
of wakerefs tracked when debugging, by passing around cookies provided
by the various rpm_get functions to their rpm_put counterpart. This
makes the pairing explicit, and given the required wakeref cookie the
compiler can verify that we pass an initialised value to the rpm_put
(quite handy for double checking error paths).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190114142129.24398-16-chris@chris-wilson.co.uk

1 files changed, 16 insertions, 9 deletions

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 951e9bae6921..33bd2addcbdd 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -83,15 +83,17 @@ static bool intel_crt_get_hw_state(struct intel_encoder *encoder,
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_crt *crt = intel_encoder_to_crt(encoder);
+	intel_wakeref_t wakeref;
 	bool ret;
 
-	if (!intel_display_power_get_if_enabled(dev_priv,
-						encoder->power_domain))
+	wakeref = intel_display_power_get_if_enabled(dev_priv,
+						     encoder->power_domain);
+	if (!wakeref)
 		return false;
 
 	ret = intel_crt_port_enabled(dev_priv, crt->adpa_reg, pipe);
 
-	intel_display_power_put(dev_priv, encoder->power_domain);
+	intel_display_power_put(dev_priv, encoder->power_domain, wakeref);
 
 	return ret;
 }
@@ -776,6 +778,7 @@ intel_crt_detect(struct drm_connector *connector,
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);
 	struct intel_crt *crt = intel_attached_crt(connector);
 	struct intel_encoder *intel_encoder = &crt->base;
+	intel_wakeref_t wakeref;
 	int status, ret;
 	struct intel_load_detect_pipe tmp;
 
@@ -784,7 +787,8 @@ intel_crt_detect(struct drm_connector *connector,
 		      force);
 
 	if (i915_modparams.load_detect_test) {
-		intel_display_power_get(dev_priv, intel_encoder->power_domain);
+		wakeref = intel_display_power_get(dev_priv,
+						  intel_encoder->power_domain);
 		goto load_detect;
 	}
 
@@ -792,7 +796,8 @@ intel_crt_detect(struct drm_connector *connector,
 	if (dmi_check_system(intel_spurious_crt_detect))
 		return connector_status_disconnected;
 
-	intel_display_power_get(dev_priv, intel_encoder->power_domain);
+	wakeref = intel_display_power_get(dev_priv,
+					  intel_encoder->power_domain);
 
 	if (I915_HAS_HOTPLUG(dev_priv)) {
 		/* We can not rely on the HPD pin always being correctly wired
@@ -847,7 +852,7 @@ load_detect:
 	}
 
 out:
-	intel_display_power_put(dev_priv, intel_encoder->power_domain);
+	intel_display_power_put(dev_priv, intel_encoder->power_domain, wakeref);
 	return status;
 }
 
@@ -857,10 +862,12 @@ static int intel_crt_get_modes(struct drm_connector *connector)
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct intel_crt *crt = intel_attached_crt(connector);
 	struct intel_encoder *intel_encoder = &crt->base;
-	int ret;
+	intel_wakeref_t wakeref;
 	struct i2c_adapter *i2c;
+	int ret;
 
-	intel_display_power_get(dev_priv, intel_encoder->power_domain);
+	wakeref = intel_display_power_get(dev_priv,
+					  intel_encoder->power_domain);
 
 	i2c = intel_gmbus_get_adapter(dev_priv, dev_priv->vbt.crt_ddc_pin);
 	ret = intel_crt_ddc_get_modes(connector, i2c);
@@ -872,7 +879,7 @@ static int intel_crt_get_modes(struct drm_connector *connector)
 	ret = intel_crt_ddc_get_modes(connector, i2c);
 
 out:
-	intel_display_power_put(dev_priv, intel_encoder->power_domain);
+	intel_display_power_put(dev_priv, intel_encoder->power_domain, wakeref);
 
 	return ret;
 }