[PATCH 1/2] drm/i915: Unconditionally flush any chipset buffers before execbuf
From: Chris Wilson <hidden>
Date: 2016-08-18 13:13:44
Also in:
intel-gfx
Subsystem:
drm drivers, intel drm i915 driver (meteor lake, dg2 and older excluding poulsbo, moorestown and derivative), the rest · Maintainers:
David Airlie, Simona Vetter, Jani Nikula, Joonas Lahtinen, Rodrigo Vivi, Tvrtko Ursulin, Linus Torvalds
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 <redacted> Cc: Akash Goel <redacted> Cc: Daniel Vetter <redacted> Cc: Tvrtko Ursulin <redacted> Tested-by: Matti Hämäläinen <redacted> Cc: stable@vger.kernel.org --- drivers/gpu/drm/i915/i915_gem_execbuffer.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 699315304748..bce587abc601 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c@@ -1015,8 +1015,6 @@ 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 +1027,11 @@ 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); - - flush_domains |= obj->base.write_domain; + i915_gem_clflush_object(obj, false); } - 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);
--
2.9.3