drm/i915: add a debugfs entry for power domain info

Add a debugfs entry showing the use-count for all power domains of each
power well.

v3: address comments from Paulo:
- simplify power_domain_str() by using a switch table
- move power_well::domain_count to power_domains
- WARN_ON decrementing a 0 refcount

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Paulo Zanoni <paulo.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 6b4f91ee486c..2f8399c347ee 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5754,8 +5754,13 @@ void intel_display_power_get(struct drm_device *dev,
 	power_domains = &dev_priv->power_domains;
 
 	mutex_lock(&power_domains->lock);
+
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+	power_domains->domain_use_count[domain]++;
+#endif
 	for_each_power_well(i, power_well, BIT(domain), power_domains)
 		__intel_power_well_get(dev, power_well);
+
 	mutex_unlock(&power_domains->lock);
 }
 
@@ -5770,8 +5775,15 @@ void intel_display_power_put(struct drm_device *dev,
 	power_domains = &dev_priv->power_domains;
 
 	mutex_lock(&power_domains->lock);
+
 	for_each_power_well_rev(i, power_well, BIT(domain), power_domains)
 		__intel_power_well_put(dev, power_well);
+
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+	WARN_ON(!power_domains->domain_use_count[domain]);
+	power_domains->domain_use_count[domain]--;
+#endif
+
 	mutex_unlock(&power_domains->lock);
 }