drm/i915: reset the GPU on context fini

It's the only way we know how to make the GPU actually forget about the
default context.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>

drivers/gpu/drm/i915/i915_drv.c

@@ -799,7 +799,7 @@ static int gen6_do_reset(struct drm_device *dev)
 	return ret;
 }
 
-static int intel_gpu_reset(struct drm_device *dev)
+int intel_gpu_reset(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int ret = -ENODEV;

drivers/gpu/drm/i915/i915_drv.h

@@ -1184,6 +1184,7 @@ extern long i915_compat_ioctl(struct file *filp, unsigned int cmd,
 extern int i915_emit_box(struct drm_device *dev,
 			 struct drm_clip_rect *box,
 			 int DR1, int DR4);
+extern int intel_gpu_reset(struct drm_device *dev);
 extern int i915_reset(struct drm_device *dev);
 extern unsigned long i915_chipset_val(struct drm_i915_private *dev_priv);
 extern unsigned long i915_mch_val(struct drm_i915_private *dev_priv);

drivers/gpu/drm/i915/i915_gem_context.c

@@ -278,6 +278,8 @@ void i915_gem_context_fini(struct drm_device *dev)
 	i915_gem_object_unpin(dev_priv->ring[RCS].default_context->obj);
 
 	do_destroy(dev_priv->ring[RCS].default_context);
+
+	intel_gpu_reset(dev);
 }
 
 void i915_gem_context_open(struct drm_device *dev, struct drm_file *file)