If userspace is asynchronously streaming into the batch or other execobjects, we may not flush those writes along with a change in cache domain (as there is no change). Therefore those writes may end up in internal chipset buffers and not visible to the GPU upon execution. We must issue a flush command or otherwise we encounter incoherency in the batchbuffers and the GPU executing invalid commands (i.e. hanging) quite regularly. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90841 Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user...") Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Akash Goel <akash.goel@xxxxxxxxx> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx> Tested-by: Matti Hämäläinen <ccr@xxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx --- drivers/gpu/drm/i915/i915_gem_execbuffer.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index 699315304748..75957aef6219 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -1016,7 +1016,6 @@ i915_gem_execbuffer_move_to_gpu(struct drm_i915_gem_request *req, const unsigned int other_rings = eb_other_engines(req); struct i915_vma *vma; uint32_t flush_domains = 0; - bool flush_chipset = false; int ret; list_for_each_entry(vma, vmas, exec_list) { @@ -1029,16 +1028,13 @@ i915_gem_execbuffer_move_to_gpu(struct drm_i915_gem_request *req, } if (obj->base.write_domain & I915_GEM_DOMAIN_CPU) - flush_chipset |= i915_gem_clflush_object(obj, false); + i915_gem_clflush_object(obj, false); flush_domains |= obj->base.write_domain; } - if (flush_chipset) - i915_gem_chipset_flush(req->engine->i915); - - if (flush_domains & I915_GEM_DOMAIN_GTT) - wmb(); + /* Unconditionally flush any chipset caches (for streaming writes). */ + i915_gem_chipset_flush(req->engine->i915); /* Unconditionally invalidate GPU caches and TLBs. */ return req->engine->emit_flush(req, EMIT_INVALIDATE); -- 2.8.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
