drm/i915: Require HW contexts (when possible)

v2: Fixed the botched locking on init_hw failure in i915_reset (Ville)
Call cleanup_ringbuffer on failed context create in init_hw (Ville)

v3: Add dev argument ti clean_ringbuffer

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
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/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e7b39d7..bc52820 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4463,7 +4463,13 @@
 	 * XXX: There was some w/a described somewhere suggesting loading
 	 * contexts before PPGTT.
 	 */
-	i915_gem_context_init(dev);
+	ret = i915_gem_context_init(dev);
+	if (ret) {
+		i915_gem_cleanup_ringbuffer(dev);
+		DRM_ERROR("Context initialization failed %d\n", ret);
+		return ret;
+	}
+
 	if (dev_priv->mm.aliasing_ppgtt) {
 		ret = dev_priv->mm.aliasing_ppgtt->enable(dev);
 		if (ret) {