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>

drivers/gpu/drm/i915/i915_drv.h

@@ -1816,6 +1816,7 @@ struct drm_i915_file_private {
 #define HAS_POWER_WELL(dev)	(IS_HASWELL(dev) || IS_BROADWELL(dev))
 #define HAS_FPGA_DBG_UNCLAIMED(dev)	(INTEL_INFO(dev)->has_fpga_dbg)
 #define HAS_PSR(dev)		(IS_HASWELL(dev) || IS_BROADWELL(dev))
+#define HAS_PC8(dev)		(IS_HASWELL(dev)) /* XXX HSW:ULX */
 
 #define INTEL_PCH_DEVICE_ID_MASK		0xff00
 #define INTEL_PCH_IBX_DEVICE_ID_TYPE		0x3b00

drivers/gpu/drm/i915/intel_display.c

@@ -6518,6 +6518,9 @@ static void __hsw_disable_package_c8(struct drm_i915_private *dev_priv)
 
 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_enable_package_c8(struct drm_i915_private *dev_priv)
 
 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 @@ static void hsw_update_package_c8(struct drm_device *dev)
 	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_update_package_c8(struct drm_device *dev)
 
 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_idle(struct drm_i915_private *dev_priv)
 
 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;