drm/i915: refactor RPM disabling due to RC6 being disabled

We can make the RPM dependency on RC6 explcit in the code by taking an
actual RPM reference, instead of avoiding to drop the initial one. This
will also enable us to remove the HAS_RUNTIME_PM special casing from
more places in the next patch.

v2:
- fixed typo in commit message (Joonas)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450203038-5150-4-git-send-email-imre.deak@intel.com

drivers/gpu/drm/i915/intel_pm.c

@@ -6014,7 +6014,17 @@ static void intel_init_emon(struct drm_device *dev)
 
 void intel_init_gt_powersave(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
 	i915.enable_rc6 = sanitize_rc6_option(dev, i915.enable_rc6);
+	/*
+	 * RPM depends on RC6 to save restore the GT HW context, so make RC6 a
+	 * requirement.
+	 */
+	if (!i915.enable_rc6) {
+		DRM_INFO("RC6 disabled, disabling runtime PM support\n");
+		intel_runtime_pm_get(dev_priv);
+	}
 
 	if (IS_CHERRYVIEW(dev))
 		cherryview_init_gt_powersave(dev);
@@ -6024,10 +6034,15 @@ void intel_init_gt_powersave(struct drm_device *dev)
 
 void intel_cleanup_gt_powersave(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
 	if (IS_CHERRYVIEW(dev))
 		return;
 	else if (IS_VALLEYVIEW(dev))
 		valleyview_cleanup_gt_powersave(dev);
+
+	if (!i915.enable_rc6)
+		intel_runtime_pm_put(dev_priv);
 }
 
 static void gen6_suspend_rps(struct drm_device *dev)

drivers/gpu/drm/i915/intel_runtime_pm.c

@@ -2306,15 +2306,6 @@ void intel_runtime_pm_enable(struct drm_i915_private *dev_priv)
 	if (!HAS_RUNTIME_PM(dev))
 		return;
 
-	/*
-	 * RPM depends on RC6 to save restore the GT HW context, so make RC6 a
-	 * requirement.
-	 */
-	if (!intel_enable_rc6(dev)) {
-		DRM_INFO("RC6 disabled, disabling runtime PM support\n");
-		return;
-	}
-
 	pm_runtime_set_autosuspend_delay(device, 10000); /* 10s */
 	pm_runtime_mark_last_busy(device);
 	pm_runtime_use_autosuspend(device);