drm/i915: Don't forget to apply SNB PIPE_CONTROL GTT workaround.

If a buffer that was the target of a PIPE_CONTROL from userland was a
reused one that hadn't been evicted which had not previously had this
workaround applied, then the early return for a correct
presumed_offset in this function meant we would not bind it into the
GTT and the write would land somewhere else.

Fixes reproducible failures with GL_EXT_timer_query usage in apitrace,
and I also expect it to fix the intermittent OQ issues on snb that
danvet's been working on.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=48019
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=52932
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Carl Worth <cworth@cworth.org>
Tested-by: Carl Worth <cworth@cworth.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 5af631e..ff2819e 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -291,6 +291,16 @@ i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,
        target_i915_obj = to_intel_bo(target_obj);
        target_offset = target_i915_obj->gtt_offset;
 
+       /* Sandybridge PPGTT errata: We need a global gtt mapping for MI and
+        * pipe_control writes because the gpu doesn't properly redirect them
+        * through the ppgtt for non_secure batchbuffers. */
+       if (unlikely(IS_GEN6(dev) &&
+           reloc->write_domain == I915_GEM_DOMAIN_INSTRUCTION &&
+           !target_i915_obj->has_global_gtt_mapping)) {
+               i915_gem_gtt_bind_object(target_i915_obj,
+                                        target_i915_obj->cache_level);
+       }
+
        /* The target buffer should have appeared before us in the
         * exec_object list, so it should have a GTT space bound by now.
         */
@@ -399,16 +409,6 @@ i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,
                io_mapping_unmap_atomic(reloc_page);
        }
 
-       /* Sandybridge PPGTT errata: We need a global gtt mapping for MI and
-        * pipe_control writes because the gpu doesn't properly redirect them
-        * through the ppgtt for non_secure batchbuffers. */
-       if (unlikely(IS_GEN6(dev) &&
-           reloc->write_domain == I915_GEM_DOMAIN_INSTRUCTION &&
-           !target_i915_obj->has_global_gtt_mapping)) {
-               i915_gem_gtt_bind_object(target_i915_obj,
-                                        target_i915_obj->cache_level);
-       }
-
        /* and update the user's relocation entry */
        reloc->presumed_offset = target_offset;