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_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index 2fc8d2f..85b9811 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -181,13 +181,13 @@
 	int slice = (int)(uintptr_t)attr->private;
 	int ret;
 
+	if (!HAS_HW_CONTEXTS(drm_dev))
+		return -ENXIO;
+
 	ret = l3_access_valid(drm_dev, offset);
 	if (ret)
 		return ret;
 
-	if (dev_priv->hw_contexts_disabled)
-		return -ENXIO;
-
 	ret = i915_mutex_lock_interruptible(drm_dev);
 	if (ret)
 		return ret;