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, 20 insertions, 15 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 1c7913b40bb7..e846608ee6aa 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -626,10 +626,12 @@ static void gen8_display_interrupt_info(struct seq_file *m)
 
 	for_each_pipe(dev_priv, pipe) {
 		enum intel_display_power_domain power_domain;
+		intel_wakeref_t wakeref;
 
 		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) {
 			seq_printf(m, "Pipe %c power disabled\n",
 				   pipe_name(pipe));
 			continue;
@@ -644,7 +646,7 @@ static void gen8_display_interrupt_info(struct seq_file *m)
 			   pipe_name(pipe),
 			   I915_READ(GEN8_DE_PIPE_IER(pipe)));
 
-		intel_display_power_put(dev_priv, power_domain);
+		intel_display_power_put(dev_priv, power_domain, wakeref);
 	}
 
 	seq_printf(m, "Display Engine port interrupt mask:\t%08x\n",
@@ -680,6 +682,8 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
 	wakeref = intel_runtime_pm_get(dev_priv);
 
 	if (IS_CHERRYVIEW(dev_priv)) {
+		intel_wakeref_t pref;
+
 		seq_printf(m, "Master Interrupt Control:\t%08x\n",
 			   I915_READ(GEN8_MASTER_IRQ));
 
@@ -695,8 +699,9 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
 			enum intel_display_power_domain power_domain;
 
 			power_domain = POWER_DOMAIN_PIPE(pipe);
-			if (!intel_display_power_get_if_enabled(dev_priv,
-								power_domain)) {
+			pref = intel_display_power_get_if_enabled(dev_priv,
+								  power_domain);
+			if (!pref) {
 				seq_printf(m, "Pipe %c power disabled\n",
 					   pipe_name(pipe));
 				continue;
@@ -706,17 +711,17 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
 				   pipe_name(pipe),
 				   I915_READ(PIPESTAT(pipe)));
 
-			intel_display_power_put(dev_priv, power_domain);
+			intel_display_power_put(dev_priv, power_domain, pref);
 		}
 
-		intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);
+		pref = intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);
 		seq_printf(m, "Port hotplug:\t%08x\n",
 			   I915_READ(PORT_HOTPLUG_EN));
 		seq_printf(m, "DPFLIPSTAT:\t%08x\n",
 			   I915_READ(VLV_DPFLIPSTAT));
 		seq_printf(m, "DPINVGTT:\t%08x\n",
 			   I915_READ(DPINVGTT));
-		intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);
+		intel_display_power_put(dev_priv, POWER_DOMAIN_INIT, pref);
 
 		for (i = 0; i < 4; i++) {
 			seq_printf(m, "GT Interrupt IMR %d:\t%08x\n",
@@ -779,10 +784,12 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
 			   I915_READ(VLV_IMR));
 		for_each_pipe(dev_priv, pipe) {
 			enum intel_display_power_domain power_domain;
+			intel_wakeref_t pref;
 
 			power_domain = POWER_DOMAIN_PIPE(pipe);
-			if (!intel_display_power_get_if_enabled(dev_priv,
-								power_domain)) {
+			pref = intel_display_power_get_if_enabled(dev_priv,
+								  power_domain);
+			if (!pref) {
 				seq_printf(m, "Pipe %c power disabled\n",
 					   pipe_name(pipe));
 				continue;
@@ -791,7 +798,7 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
 			seq_printf(m, "Pipe %c stat:\t%08x\n",
 				   pipe_name(pipe),
 				   I915_READ(PIPESTAT(pipe)));
-			intel_display_power_put(dev_priv, power_domain);
+			intel_display_power_put(dev_priv, power_domain, pref);
 		}
 
 		seq_printf(m, "Master IER:\t%08x\n",
@@ -1709,8 +1716,7 @@ static int i915_sr_status(struct seq_file *m, void *unused)
 	intel_wakeref_t wakeref;
 	bool sr_enabled = false;
 
-	wakeref = intel_runtime_pm_get(dev_priv);
-	intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);
+	wakeref = intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);
 
 	if (INTEL_GEN(dev_priv) >= 9)
 		/* no global SR status; inspect per-plane WM */;
@@ -1726,8 +1732,7 @@ static int i915_sr_status(struct seq_file *m, void *unused)
 	else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
 		sr_enabled = I915_READ(FW_BLC_SELF_VLV) & FW_CSPWRDWNEN;
 
-	intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);
-	intel_runtime_pm_put(dev_priv, wakeref);
+	intel_display_power_put(dev_priv, POWER_DOMAIN_INIT, wakeref);
 
 	seq_printf(m, "self-refresh: %s\n", enableddisabled(sr_enabled));