drm/i915/guc: Fix runtime suspend

We are not allowed to rpm_get() inside the runtime-suspend callback, so
split the intel_uc_suspend() into the core that assumes the caller holds
the wakeref (intel_uc_runtime_suspend), and one that acquires the wakeref
as necessary (intel_uc_suspend).
Reported-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Fixes: 79ffac85 ("drm/i915: Invert the GEM wakeref hierarchy")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190502203009.15727-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_drv.c

@@ -2890,7 +2890,7 @@ static int intel_runtime_suspend(struct device *kdev)
 	 */
 	i915_gem_runtime_suspend(dev_priv);
 
-	intel_uc_suspend(dev_priv);
+	intel_uc_runtime_suspend(dev_priv);
 
 	intel_runtime_pm_disable_interrupts(dev_priv);
 

drivers/gpu/drm/i915/intel_uc.c

@@ -481,22 +481,31 @@ void intel_uc_reset_prepare(struct drm_i915_private *i915)
 	intel_uc_sanitize(i915);
 }
 
-void intel_uc_suspend(struct drm_i915_private *i915)
+void intel_uc_runtime_suspend(struct drm_i915_private *i915)
 {
 	struct intel_guc *guc = &i915->guc;
-	intel_wakeref_t wakeref;
 	int err;
 
 	if (guc->fw.load_status != INTEL_UC_FIRMWARE_SUCCESS)
 		return;
 
-	with_intel_runtime_pm(i915, wakeref) {
 	err = intel_guc_suspend(guc);
 	if (err)
 		DRM_DEBUG_DRIVER("Failed to suspend GuC, err=%d", err);
 
 	guc_disable_communication(guc);
-	}
+}
+
+void intel_uc_suspend(struct drm_i915_private *i915)
+{
+	struct intel_guc *guc = &i915->guc;
+	intel_wakeref_t wakeref;
+
+	if (guc->fw.load_status != INTEL_UC_FIRMWARE_SUCCESS)
+		return;
+
+	with_intel_runtime_pm(i915, wakeref)
+		intel_uc_runtime_suspend(i915);
 }
 
 int intel_uc_resume(struct drm_i915_private *i915)

drivers/gpu/drm/i915/intel_uc.h

@@ -40,6 +40,7 @@ int intel_uc_init(struct drm_i915_private *dev_priv);
 void intel_uc_fini(struct drm_i915_private *dev_priv);
 void intel_uc_reset_prepare(struct drm_i915_private *i915);
 void intel_uc_suspend(struct drm_i915_private *i915);
+void intel_uc_runtime_suspend(struct drm_i915_private *i915);
 int intel_uc_resume(struct drm_i915_private *dev_priv);
 
 static inline bool intel_uc_is_using_guc(struct drm_i915_private *i915)