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drm/i915: implement SNB workaround for lazy global gtt

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PIPE_CONTROL on snb needs global gtt mappings in place to workaround a
hw gotcha. No other commands need such a workaround. Luckily we can
detect a PIPE_CONTROL commands easily because they have a write_domain
= I915_GEM_DOMAIN_INSTRUCTION (and nothing else has that).

v2: Binding the target of such a reloc into the global gtt actually
works instead of binding the source, which is rather pointless ...

v3: Kill a superflous has_global_gtt_mapping assignement noticed by
Chris Wilson.

Reviewed-and-tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Daniel Vetter 2012-02-15 23:50:23 +01:00
parent 74898d7edc
commit 149c84077f
1 changed files with 13 additions and 1 deletions
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14
drivers/gpu/drm/i915/i915_gem_execbuffer.c
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@ -273,6 +273,7 @@ i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,
{
struct drm_device *dev = obj->base.dev;
struct drm_gem_object *target_obj;
struct drm_i915_gem_object *target_i915_obj;
uint32_t target_offset;
int ret = -EINVAL;
@ -281,7 +282,8 @@ i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,
if (unlikely(target_obj == NULL))
return -ENOENT;
target_offset = to_intel_bo(target_obj)->gtt_offset;
target_i915_obj = to_intel_bo(target_obj);
target_offset = target_i915_obj->gtt_offset;
/* The target buffer should have appeared before us in the
* exec_object list, so it should have a GTT space bound by now.
@ -383,6 +385,16 @@ 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;