drm/i915: Remove stop-rings debugfs interface

Now that we have (near) universal GPU recovery code, we can inject a
real hang from userspace and not need any fakery. Not only does this
mean that the testing is far more realistic, but we can simplify the
kernel in the process.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Arun Siluvery <arun.siluvery@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467616119-4093-7-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 40521a3..7b9b6f9 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -2159,24 +2159,11 @@
 		goto error;
 	}
 
+	pr_notice("drm/i915: Resetting chip after gpu hang\n");
+
 	i915_gem_reset(dev);
 
 	ret = intel_gpu_reset(dev_priv, ALL_ENGINES);
-
-	/* Also reset the gpu hangman. */
-	if (error->stop_rings != 0) {
-		DRM_INFO("Simulated gpu hang, resetting stop_rings\n");
-		error->stop_rings = 0;
-		if (ret == -ENODEV) {
-			DRM_INFO("Reset not implemented, but ignoring "
-				 "error for simulated gpu hangs\n");
-			ret = 0;
-		}
-	}
-
-	if (i915_stop_ring_allow_warn(dev_priv))
-		pr_notice("drm/i915: Resetting chip after gpu hang\n");
-
 	if (ret) {
 		if (ret != -ENODEV)
 			DRM_ERROR("Failed to reset chip: %i\n", ret);