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, 5 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 6adcc8d037bf..b01aacb5d73d 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -94,15 +94,17 @@ static bool intel_lvds_get_hw_state(struct intel_encoder *encoder,
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
+	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_lvds_port_enabled(dev_priv, lvds_encoder->reg, pipe);
 
-	intel_display_power_put(dev_priv, encoder->power_domain);
+	intel_display_power_put(dev_priv, encoder->power_domain, wakeref);
 
 	return ret;
 }