drm/i915: Do not enable package C8 on unsupported hardware

If the hardware does not support package C8, then do not even schedule
work to enable it. Thereby we can eliminate a bunch of dangerous work.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0b77916..7ec8b48 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6518,6 +6518,9 @@
 
 void hsw_enable_package_c8(struct drm_i915_private *dev_priv)
 {
+	if (!HAS_PC8(dev_priv->dev))
+		return;
+
 	mutex_lock(&dev_priv->pc8.lock);
 	__hsw_enable_package_c8(dev_priv);
 	mutex_unlock(&dev_priv->pc8.lock);
@@ -6525,6 +6528,9 @@
 
 void hsw_disable_package_c8(struct drm_i915_private *dev_priv)
 {
+	if (!HAS_PC8(dev_priv->dev))
+		return;
+
 	mutex_lock(&dev_priv->pc8.lock);
 	__hsw_disable_package_c8(dev_priv);
 	mutex_unlock(&dev_priv->pc8.lock);
@@ -6562,6 +6568,9 @@
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	bool allow;
 
+	if (!HAS_PC8(dev_priv->dev))
+		return;
+
 	if (!i915_enable_pc8)
 		return;
 
@@ -6585,6 +6594,9 @@
 
 static void hsw_package_c8_gpu_idle(struct drm_i915_private *dev_priv)
 {
+	if (!HAS_PC8(dev_priv->dev))
+		return;
+
 	mutex_lock(&dev_priv->pc8.lock);
 	if (!dev_priv->pc8.gpu_idle) {
 		dev_priv->pc8.gpu_idle = true;
@@ -6595,6 +6607,9 @@
 
 static void hsw_package_c8_gpu_busy(struct drm_i915_private *dev_priv)
 {
+	if (!HAS_PC8(dev_priv->dev))
+		return;
+
 	mutex_lock(&dev_priv->pc8.lock);
 	if (dev_priv->pc8.gpu_idle) {
 		dev_priv->pc8.gpu_idle = false;