drm/i915: Avoid BUG_ONs on VT switch with a wedged chipset.

Instead, just warn that bad things are happening and do our best to clean up
the mess without the GPU's help.

Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 39 insertions, 14 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6b4a2bd20640..edc805afde05 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -31,6 +31,8 @@
 #include "i915_drv.h"
 #include <linux/swap.h>
 
+#define I915_GEM_GPU_DOMAINS    (~(I915_GEM_DOMAIN_CPU | I915_GEM_DOMAIN_GTT))
+
 static int
 i915_gem_object_set_domain(struct drm_gem_object *obj,
                             uint32_t read_domains,
@@ -2299,29 +2301,52 @@ i915_gem_idle(struct drm_device *dev)
 
         i915_gem_retire_requests(dev);
 
-        /* Active and flushing should now be empty as we've
-         * waited for a sequence higher than any pending execbuffer
-         */
-        BUG_ON(!list_empty(&dev_priv->mm.active_list));
-        BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
+        if (!dev_priv->mm.wedged) {
+                /* Active and flushing should now be empty as we've
+                 * waited for a sequence higher than any pending execbuffer
+                 */
+                WARN_ON(!list_empty(&dev_priv->mm.active_list));
+                WARN_ON(!list_empty(&dev_priv->mm.flushing_list));
+                /* Request should now be empty as we've also waited
+                 * for the last request in the list
+                 */
+                WARN_ON(!list_empty(&dev_priv->mm.request_list));
+        }
 
-        /* Request should now be empty as we've also waited
-         * for the last request in the list
+        /* Empty the active and flushing lists to inactive.  If there's
+         * anything left at this point, it means that we're wedged and
+         * nothing good's going to happen by leaving them there.  So strip
+         * the GPU domains and just stuff them onto inactive.
          */
-        BUG_ON(!list_empty(&dev_priv->mm.request_list));
+        while (!list_empty(&dev_priv->mm.active_list)) {
+                struct drm_i915_gem_object *obj_priv;
+
+                obj_priv = list_first_entry(&dev_priv->mm.active_list,
+                                            struct drm_i915_gem_object,
+                                            list);
+                obj_priv->obj->write_domain &= ~I915_GEM_GPU_DOMAINS;
+                i915_gem_object_move_to_inactive(obj_priv->obj);
+        }
+
+        while (!list_empty(&dev_priv->mm.flushing_list)) {
+                struct drm_i915_gem_object *obj_priv;
+
+                obj_priv = list_first_entry(&dev_priv->mm.active_list,
+                                            struct drm_i915_gem_object,
+                                            list);
+                obj_priv->obj->write_domain &= ~I915_GEM_GPU_DOMAINS;
+                i915_gem_object_move_to_inactive(obj_priv->obj);
+        }
+
 
-        /* Move all buffers out of the GTT. */
+        /* Move all inactive buffers out of the GTT. */
         ret = i915_gem_evict_from_list(dev, &dev_priv->mm.inactive_list);
+        WARN_ON(!list_empty(&dev_priv->mm.inactive_list));
         if (ret) {
                 mutex_unlock(&dev->struct_mutex);
                 return ret;
         }
 
-        BUG_ON(!list_empty(&dev_priv->mm.active_list));
-        BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
-        BUG_ON(!list_empty(&dev_priv->mm.inactive_list));
-        BUG_ON(!list_empty(&dev_priv->mm.request_list));
-
         i915_gem_cleanup_ringbuffer(dev);
         mutex_unlock(&dev->struct_mutex);