The initialized flag is used to specify a context has been initialized and it's context is safe to load, ie. the 3d state is setup properly. With full PPGTT, we emit the address space loads during context switch and this currently marks a context as initialized. With full PPGTT patches, if a client first emits a batch to !RCS, then later, RCS, the code will mistake the context as initialized and try to reload an uninitialized context. 1. context 1 blit // context marked as initialized 2. context 1 render // loads random state It is really easy to hit this with a planned upcoming patch which makes default context reuse possible. See the mailing list thread in references for more details about the issue. Thanks to Chris for helping me track this down. References: <1388266309-1178-1-git-send-email-benjamin.widawsky@xxxxxxxxx> Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Signed-off-by: Ben Widawsky <ben@xxxxxxxxxxxx> --- drivers/gpu/drm/i915/i915_gem_context.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c index 44dddc00..8c7a5b2 100644 --- a/drivers/gpu/drm/i915/i915_gem_context.c +++ b/drivers/gpu/drm/i915/i915_gem_context.c @@ -692,10 +692,11 @@ static int do_switch(struct intel_ring_buffer *ring, i915_gem_context_unreference(from); } + to->is_initialized = true; + done: i915_gem_context_reference(to); ring->last_context = to; - to->is_initialized = true; to->last_ring = ring; return 0; -- 1.8.5.2 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
