Doing mixed rendering into the front/back scanout buffers lead to the
interesting rediscovery of clflushing when page-flipping. A painful
experience indeed.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_gem.c | 7 +++++--
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 4eee0bf..569475b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -865,6 +865,7 @@ struct drm_i915_gem_object {
unsigned int fenced_gpu_access:1;
unsigned int cache_level:2;
+ unsigned int cache_dirty:2;
unsigned int has_aliasing_ppgtt_mapping:1;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index eb63c69..8e547dd 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2907,12 +2907,15 @@ i915_gem_clflush_object(struct drm_i915_gem_object *obj)
* snooping behaviour occurs naturally as the result of our domain
* tracking.
*/
- if (obj->cache_level != I915_CACHE_NONE)
+ if (obj->cache_level != I915_CACHE_NONE) {
+ obj->cache_dirty = obj->cache_level;
return;
+ }
trace_i915_gem_object_clflush(obj);
drm_clflush_pages(obj->pages, obj->base.size / PAGE_SIZE);
+ obj->cache_dirty = I915_CACHE_NONE;
}
/** Flushes any GPU write domain for the object if it's dirty. */
@@ -3066,7 +3069,7 @@ int i915_gem_object_set_cache_level(struct
drm_i915_gem_object *obj,
obj, cache_level);
}
- if (cache_level == I915_CACHE_NONE) {
+ if (obj->cache_dirty) {
u32 old_read_domains, old_write_domain;
/* If we're coming from LLC cached, then we haven't
--
1.7.9.1
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