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, 9 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/vlv_dsi.c b/drivers/gpu/drm/i915/vlv_dsi.c
index bb1287020f80..d116fead8514 100644
--- a/drivers/gpu/drm/i915/vlv_dsi.c
+++ b/drivers/gpu/drm/i915/vlv_dsi.c
@@ -959,13 +959,15 @@ static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+	intel_wakeref_t wakeref;
 	enum port port;
 	bool active = false;
 
 	DRM_DEBUG_KMS("\n");
 
-	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;
 
 	/*
@@ -1021,7 +1023,7 @@ static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
 	}
 
 out_put_power:
-	intel_display_power_put(dev_priv, encoder->power_domain);
+	intel_display_power_put(dev_priv, encoder->power_domain, wakeref);
 
 	return active;
 }
@@ -1574,6 +1576,7 @@ vlv_dsi_get_hw_panel_orientation(struct intel_connector *connector)
 	enum drm_panel_orientation orientation;
 	struct intel_plane *plane;
 	struct intel_crtc *crtc;
+	intel_wakeref_t wakeref;
 	enum pipe pipe;
 	u32 val;
 
@@ -1584,7 +1587,8 @@ vlv_dsi_get_hw_panel_orientation(struct intel_connector *connector)
 	plane = to_intel_plane(crtc->base.primary);
 
 	power_domain = POWER_DOMAIN_PIPE(pipe);
-	if (!intel_display_power_get_if_enabled(dev_priv, power_domain))
+	wakeref = intel_display_power_get_if_enabled(dev_priv, power_domain);
+	if (!wakeref)
 		return DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
 
 	val = I915_READ(DSPCNTR(plane->i9xx_plane));
@@ -1596,7 +1600,7 @@ vlv_dsi_get_hw_panel_orientation(struct intel_connector *connector)
 	else
 		orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
 
-	intel_display_power_put(dev_priv, power_domain);
+	intel_display_power_put(dev_priv, power_domain, wakeref);
 
 	return orientation;
 }