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

Eric Anholt
2012-07-31T22:35:01Z

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
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>
---
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 25b2c54..afb312e 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -117,6 +117,16 @@ 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.
*/
@@ -225,16 +235,6 @@ 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;

--
1.7.10.4