drm/i915: Only sanitize GEM from late suspend

During testing we encounter a conflict between SUSPEND_TEST_DEVICES and
disabling reset (gem_eio/suspend). This results in the device continuing
on without being reset, but since it has gone through HW sanitization to
account for the suspend/resume cycle, we have to assume the device has
been reset to its defaults. A simple way around this is to skip the
sanitize phase for SUSPEND_TEST_DEVICES by moving it to suspend-late.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180531082246.9763-4-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -5055,6 +5055,17 @@ int i915_gem_suspend(struct drm_i915_private *dev_priv)
 	if (WARN_ON(!intel_engines_are_idle(dev_priv)))
 		i915_gem_set_wedged(dev_priv); /* no hope, discard everything */
 
+	intel_runtime_pm_put(dev_priv);
+	return 0;
+
+err_unlock:
+	mutex_unlock(&dev->struct_mutex);
+	intel_runtime_pm_put(dev_priv);
+	return ret;
+}
+
+void i915_gem_suspend_late(struct drm_i915_private *i915)
+{
 	/*
 	 * Neither the BIOS, ourselves or any other kernel
 	 * expects the system to be in execlists mode on startup,
@@ -5074,16 +5085,9 @@ int i915_gem_suspend(struct drm_i915_private *dev_priv)
 	 * machines is a good idea, we don't - just in case it leaves the
 	 * machine in an unusable condition.
 	 */
-	intel_uc_sanitize(dev_priv);
-	i915_gem_sanitize(dev_priv);
 
-	intel_runtime_pm_put(dev_priv);
-	return 0;
-
-err_unlock:
-	mutex_unlock(&dev->struct_mutex);
-	intel_runtime_pm_put(dev_priv);
-	return ret;
+	intel_uc_sanitize(i915);
+	i915_gem_sanitize(i915);
 }
 
 void i915_gem_resume(struct drm_i915_private *i915)