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, 24 insertions, 12 deletions

diff --git a/drivers/gpu/drm/i915/icl_dsi.c b/drivers/gpu/drm/i915/icl_dsi.c
index 4dd793b78996..f3a5f03646ce 100644
--- a/drivers/gpu/drm/i915/icl_dsi.c
+++ b/drivers/gpu/drm/i915/icl_dsi.c
@@ -337,9 +337,11 @@ static void gen11_dsi_enable_io_power(struct intel_encoder *encoder)
 	}
 
 	for_each_dsi_port(port, intel_dsi->ports) {
-		intel_display_power_get(dev_priv, port == PORT_A ?
-					POWER_DOMAIN_PORT_DDI_A_IO :
-					POWER_DOMAIN_PORT_DDI_B_IO);
+		intel_dsi->io_wakeref[port] =
+			intel_display_power_get(dev_priv,
+						port == PORT_A ?
+						POWER_DOMAIN_PORT_DDI_A_IO :
+						POWER_DOMAIN_PORT_DDI_B_IO);
 	}
 }
 
@@ -1125,10 +1127,18 @@ static void gen11_dsi_disable_io_power(struct intel_encoder *encoder)
 	enum port port;
 	u32 tmp;
 
-	intel_display_power_put(dev_priv, POWER_DOMAIN_PORT_DDI_A_IO);
-
-	if (intel_dsi->dual_link)
-		intel_display_power_put(dev_priv, POWER_DOMAIN_PORT_DDI_B_IO);
+	for_each_dsi_port(port, intel_dsi->ports) {
+		intel_wakeref_t wakeref;
+
+		wakeref = fetch_and_zero(&intel_dsi->io_wakeref[port]);
+		if (wakeref) {
+			intel_display_power_put(dev_priv,
+						port == PORT_A ?
+						POWER_DOMAIN_PORT_DDI_A_IO :
+						POWER_DOMAIN_PORT_DDI_B_IO,
+						wakeref);
+		}
+	}
 
 	/* set mode to DDI */
 	for_each_dsi_port(port, intel_dsi->ports) {
@@ -1229,13 +1239,15 @@ static bool gen11_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);
-	u32 tmp;
-	enum port port;
 	enum transcoder dsi_trans;
+	intel_wakeref_t wakeref;
+	enum port port;
 	bool ret = false;
+	u32 tmp;
 
-	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;
 
 	for_each_dsi_port(port, intel_dsi->ports) {
@@ -1260,7 +1272,7 @@ static bool gen11_dsi_get_hw_state(struct intel_encoder *encoder,
 		ret = tmp & PIPECONF_ENABLE;
 	}
 out:
-	intel_display_power_put(dev_priv, encoder->power_domain);
+	intel_display_power_put(dev_priv, encoder->power_domain, wakeref);
 	return ret;
 }