drm/i915: catch forcewake reference underruns
Without this the new drv_suspend/forcewake subtest I've created
doesn't result in immediately visible failures.
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index ab5165c..c3832d9 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -280,12 +280,17 @@
spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
- if (fw_engine & FORCEWAKE_RENDER &&
- --dev_priv->uncore.fw_rendercount != 0)
- fw_engine &= ~FORCEWAKE_RENDER;
- if (fw_engine & FORCEWAKE_MEDIA &&
- --dev_priv->uncore.fw_mediacount != 0)
- fw_engine &= ~FORCEWAKE_MEDIA;
+ if (fw_engine & FORCEWAKE_RENDER) {
+ WARN_ON(!dev_priv->uncore.fw_rendercount);
+ if (--dev_priv->uncore.fw_rendercount != 0)
+ fw_engine &= ~FORCEWAKE_RENDER;
+ }
+
+ if (fw_engine & FORCEWAKE_MEDIA) {
+ WARN_ON(!dev_priv->uncore.fw_mediacount);
+ if (--dev_priv->uncore.fw_mediacount != 0)
+ fw_engine &= ~FORCEWAKE_MEDIA;
+ }
if (fw_engine)
dev_priv->uncore.funcs.force_wake_put(dev_priv, fw_engine);
@@ -301,6 +306,8 @@
assert_device_not_suspended(dev_priv);
spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
+ WARN_ON(!dev_priv->uncore.forcewake_count);
+
if (--dev_priv->uncore.forcewake_count == 0)
dev_priv->uncore.funcs.force_wake_put(dev_priv, FORCEWAKE_ALL);
spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
@@ -452,6 +459,8 @@
spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
+ WARN_ON(!dev_priv->uncore.forcewake_count);
+
if (--dev_priv->uncore.forcewake_count == 0) {
dev_priv->uncore.forcewake_count++;
delayed = true;